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Practical 
Preventive  Medicine 


BY 

MARK  F.  BOYD,  M.D.,  M.S.,  C.P.H. 

Professor  of  Bacteriology  and  Preventive  Medicine  in  the  Medical 
Department  of  the  University  of  Texas;  Passed  Assistant  Surgeon, 
(Reserve)  U.  S.  Public  Health  Service;  Formerly  Epidemiologist 
of  the  Iowa  State  Board  of  Health  and  Associate  Professor  of 
Preventive  Medicine  in  the  College  of  Medicine  of  the  University 
of  Iowa;  Charles  Follen  Folsom  Teaching  Fellow  in  Hygiene, 
Harvard  Medical  School 


135  ILLUSTRATIONS 


PHILADELPHIA   AND  LONDON 

W.   B.    SAUNDERS   COMPANY 

1920 


Copyright,  1920.  by  W.  B.  Saunders  Company 


PRINTED    IN   AMERICA 

PRESS  OF 

W.     B.     8AUNDER8    COMPANY 

PHILADELPHIA 


TO  MY  PARENTS 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/practicalpreventOOboyd 


FOREWORD 


The  following  pages  represent  an  endeavor  to  briefly  present 
the  salient  features  of  modern  preventive  medicine.  In  a 
desire  to  cover  the  entire  field,  a  great  condensation  has  been 
effected,  which  in  many  instances  perhaps  results  in  an  in- 
adequate consideration  of  important  subjects.  It  is  believed 
this  represents  the  minimum  knowledge  of  the  subject  which  a 
student  of  medicine  or  a  practitioner  of  medicine  should  be 
expected  to  possess. 

While  admittedly  brief,  the  student  or  reader  desiring  a 
broader  knowledge  will  be  assisted  by  the  numerous  references 
given.  These  have  been  particularly  designed  to  introduce 
the  student  to  the  vast  stores  of  public  health  literature  which 
exist  in  the  publications  of  various  departments  of  the  United 
States  government.  Any  individual  especially  interested  in 
this  field  should  make  every  effort  to  acquire  those  listed- and 
keep  in  touch  with  the  new  publications  issued. 

The  medical  profession  can  play  an  important  role  in  the 
field  of  preventive  medicine  and  public  health.  At  present 
physicians  are  neglecting  their  opportunities..  If  this  neglect 
continues  the  opportunities  will  lessen  and  the  field  will  be 
taken  away  from  physicians  by  a  changing  public  sentiment. 
If  these  pages  will  bring  home  to  medical  students  and  prac- 
titioners a  realization  of  their  public  health  responsibilities 
and  stimulate  co-operation  with  public  health  authorities,  the 
labor  of  their  preparation  will  have  been  abundantly  rewarded. 

No  originality  is  claimed  for  the  material  here  presented. 
All  available  sources  of  information  have  been  freely  utilized. 
Special  acknowledgement  should  be  made  of  the  utilization  of 
Rosenau's  "Preventive  Medicine  and  Hygiene"  to  which 
the  specialist  or  advanced  student  will  naturally  turn,  and  to 
the  report  of  the  Committee  on  Standard  Regulations  of  the 
American  Public  Health  Association. 

Mark  F.  Boyd. 

Galveston,  Texas, 
November,  1920 

11 


CONTENTS 

CHAPTER  I 

Page 

Introduction     I7 

SECTION  I 

DISEASES    DUE  TO   INVADING   MICRO-ORGAN- 
ISMS:  EPIDEMIOLOGY 

CHAPTER  II 

Sources  of  Infection      24 

CHAPTER  III 
Dissemination  of  Infective  Agents 29 

CHAPTER  IV 
Contact  Transmission 33 

CHAPTER  V 
Diseases  Transmitted  Solely  by  Contact ^1 

CHAPTER  VI 
Diseases  Usually  Transmitted  by  Contact 48 

CHAPTER  VII 

Diseases  Usually  Transmitted  by  Contact  (Continued)       54 

CHAPTER  VIII 

Diseases  Usually  Transmitted  by  Contact  {Continued)        .......     59 

CHAPTER  IX 

Diseases  Frequently  Transmitted  by  Contact      67 

CHAPTER  X 

General  Measures  of  Disease  Control 74 

CHAPTER  XI 

General  Measures  of  Disease  Control  {Continued)     83 

CHAPTER  XII 

Disinfectants  and  Disinfection 94 

CHAPTER  XIII 

Excreta  Disposal 104. 

13 


14  CONTENTS 

CHAPTER  XIV 

Page 

Excreta  Disposal  (Continued)       , 114 

CHAPTER  XV 

Relationship  of  Water  to  Health  and  Disease 124 

CHAPTER  XVI 

Water  Purification . 131 

CHAPTER  XVII 

Production  and  Inspection  of  Milk 149 

CHAPTER  XVIII 

Milk  as  a  Route  of  Infection 167 

CHAPTER  XIX 
Other  Food  Stuffs  as  Routes  of  Infection  . 175 

CHAPTER  XX 

Insects  as  Vectors  of  Infective  Agents 180 

CHAPTER  XXI 
Diseases  Transmissible  by  Insects     188 

CHAPTER  XXII 

Lower  Animals  as  Sources  of  Infection  for  Man 203 

CHAPTER  XXIII 

Other  Aspects  of  Infectious  Diseases 220 

SECTION  II 
DEFICIENCY  DISEASES 

CHAPTER  XXIV 

Food  Requirements:  Production  and  Retail J.    .    .   223 

CHAPTER  XXV 
Diseases  Due  to  Dietary  Deficiencies 229 

SECTION  III 
OCCUPATIONAL  DISEASES 

CHAPTER  XXVI 
Hazards  of  Occupation 236 

CHAPTER  XXVII 

Occupational  Intoxications  and  Diseases 245 


CONTENTS  15 

SECTION  IV 

CHAPTER  XXVIII 

Page 
Diseases  Arising  From  the  Puerperal  State 255 

SECTION  V 

CHAPTER  XXIX 
Diseases  Transmitted  from  Parent  to  Offspring      260 

SECTION  VI 

SPECIAL  ASPECTS    OF   HYGIENE   AND 
SANITATION 

CHAPTER  XXX 

Hygiene  of  Infancy        267 

CHAPTER  XXXI 

Hygiene  of  Childhood 275 

CHAPTER  XXXII 
Air:  Heating  and  Ventilation 282 

CHAPTER  XXXIII 
Certain  Aspects  of  Personal  Hygiene     288 

CHAPTER  XXXIV 
Domestic  Sanitation 295 

SECTION  VII 
DEMOGRAPHY 

CHAPTER  XXXV 
Statistics  of  Population 301 

CHAPTER  XXXVI 
Statistics  of  Births  and  Deaths 312 

CHAPTER  XXXVII 

Statistics  of  Sickness 323 

SECTION  VIII 
PUBLIC  HEALTH 

CHAPTER  XXXVIII 
Public  Health  Administration 328 

Index 337 


PRACTICAL  PREVENTIVE  MEDICINE 

CHAPTER    I 
INTRODUCTION 

Preventive  Medicine  may  be  defined  as  that  branch  of  applied 
biology  which  seeks  to  reduce  or  eradicate  disease  by  removing 
or  altering  the  responsible  etiological  factors.  Included  within 
its  scope  are  two  subjects  which  are  often  confused  with  it, 
these  are  hygiene  and  sanitation  respectively.  Hygiene  is  the 
proper  care  of.  the  body  to  permit  the  normal  functioning  of  the 
various  organs  and  tissues,  while  sanitation  is  the  proper  clean- 
liness of  the  environment. 

Since  preventive  medicine  requires  a  complete  knowledge 
of  the  etiology  of  disease  for  its  application,  it  is  apparent 
that  deficiencies  of  etiologic  knowledge  must  necessarily  limit 
the  scope  of  successful  work.  There  are  however  five  groups 
of  diseases  whose  etiology  is  sufficiently  well  known  to  warrant 
their  classification  as  preventable.     The  groups  are: 

(I)  Diseases  produced  as  the  result  of  the  invasion  of  the 
body  by  micro-organisms; 

(II)  Diseases  the  result  of  a  faulty  or  deficient  diet; 

(III)  Diseases  the  result  of  unhygienic  or  insanitary  conditions 
of  employment; 

(IV)  Diseases  arising  as  the  result  of  the  puerperal  state;  and 
(V)  Diseases  transmitted  from  parent  to  offspring. 
Despite  the  fact  that  the  number  of  diseases  included  in  the 

above  groups  is  limited,  this  handicap  is  very  much  reduced  by 
the  fact  that  the  diseases  included  in  the  above  groups  are  for 
the  most  part,  of  considerable  importance  as  causes  of  morbidity 
and  mortality,  so  that  effective  control  measures  directed  against 
them  will  accomplish  a  great  deal  in  reducing  the  hazards  of 
life.  Their  importance  may  be  judged  from  the  following  mor- 
tality statistics  from  the  registration  area  of  the  United 
States: 

2  17 


1 8  PRACTICAL  PREVENTIVE  MEDICINE 

TABLE  I 

1912  1913 

Per  cent,  of  total  population  of  U.  S.  in  registration  area.  ..  .           63.2  65.1 

Total  deaths,  all  causes 838,251  890,848 

Deaths,  disease  of  group  1 287,645  304,580 

Deaths,  disease  of  group  2 4,409  15,005 

Deaths,  disease  of  group  3 156  171 

Deaths,  disease  of  group  4 9,035  10,010 

Deaths,  disease  of  group  5 Not  a  direct  cause 

of   death. 

While  the  diseases  of  group  5  are  not  of  importance  as  causes 
of  mortality,  they  nevertheless  exert  a  certain  definite  influence 
which  we  will  consider  later. 

Directly  as  well  as  indirectly  these  diseases  are  the  cause  of 
immense  economic  losses.  These  affect  both  the  individual 
and  the  social  fabric.  The  following  economic  losses  may  be 
enumerated: 

(a)  Temporary  or  permanent  disablement  of  the  patient 
as  an  immediate  result  of  the  disease,  resulting  to  the  individual 
in  temporary  or  permanent  loss  of  earning,  and  to  society  in 
the  loss  of  productive  labor; 

(b)  Sequela?  or  complications  which  permanently  impair  the 
individuals  usefulness  or  hasten  death  from  other  causes; 

(c)  Expenses  of  illness,  which  if  due  to  preventable  illness, 
must  be  regarded  as  an  economic  loss; 

(d)  The  expense  incident  to  the  establishment  and  main- 
tenance of  public  hospitals,  asylums  and  charitable  agencies  to 
relieve  want  arising  from  disabling  sickness; 

(e)  Making  vast  regions  of  the  earth's  surface  uninhabitable 
for  the  civilized  races;  while 

(/")  Preventable  diseases  of  the  domesticated  food  producing 
animals  may  cause  such  inroads  into  their  numbers  that  animal 
foods  become  scarce  and  consequently  high  in  price.  This  is 
due  both  to  a  destruction  of  the  animals  as  well  as  to  a  decreased 
productiveness  of  those  surviving. 

With  most  of  the  diseases  included  in  the  foregoing  groups 
our  available  knowledge  is  sufficiently  adequate  to  justify  us  in 
classifying  them  as  preventable.  Their  continued  presence 
with  us  is  chiefly  due  to  the  lack  of  ways  and  means  for  placing 
effective  control  measures  in  operation.  It  may  never  be 
practicable  to  place  in  operation  in  civil  life  the  drastic,  but 
nevertheless  effective  measures  which  have  made  the  military 
application  of  preventive  medicine  so  brilliant,  though  the  ex- 
perience with  military  discipline  emphasizes  the  administrative 


INTRODUCTION  1 9 

difficulties  which  are  encountered  in  the  civil  application  of 
these  measures,  where  tact  rather  than  force  must  win  the  point. 
Conceiving  a  population  wherein  an  adequately  organized  defen- 
sive and  offensive  body  was  available  to  apply  proper  measures, 
we  might  expect  that  their  continued  application  would  have 
certain  effects.     Among  these  we  may  prophesy  the  following: 

(a)  An  increase  in  the  period  of  expectation  of  life,  that  is ' 
the  probable  duration  of  the  life  of  the  hypothetical  average 
individual.  This  change  will  be  accompanied  by  the  following 
phenomena:  (i)  There  will  first  be  a  gradual  diminution  in 
the  total  death  rate,  due  to  the  gradual  disappearance  of  the 
preventable  diseases  as  causes  of  mortality;  (2)  A  change  in 
the  age  distribution  of  the  deaths  will  next  be  apparent.  The 
majority  of  the  conditions  we  are  considering  are  most  active  as 
causes  of  death  among  the  ages  below  thirty.  Their  elimination 
will  of  course  permit  a  larger  proportion  of  individuals  to  survive 
to  ages  beyond  thirty,  and  as  the  change  takes  place  the  number 
of  deaths  above  thirty  will  slowly  increase,  proportionate  to 
the  decrease  in  the  deaths  below  thirty.  (3)  The  conditions 
which  are  operative  as  causes  of  death  at  the  age  periods  beyond 
thirty,  other  than  those  of  our  particular  groups  will  gradually 
be  found  to  be  responsible  for  an  increasingly  greater  number  of 
deaths.  This  state  of  affairs  is  not  necessarily  alarming,  but 
rather  is  encouraging,  as  indicating  that  a  larger  proportion  of 
individuals  are  permitted  to  survive  to  middle  life  and  older 
periods.  This  is,  in  our  opinion,  the  most  rational  explanation 
of  the  increases  which  have  been  observed  in  the  mortality 
from  carcinoma  and  cardio-renal  disease.  The  completion  of 
this  cycle  of  transformation  will  probably  leave  us  with  a  crude 
death  rate  from  all  causes  very  nearly  the  same  as  before  the 
days  of  even  the  most  feeble  preventive  work.  The  important 
difference  will  be  in  the  age  distribution  of  the  deaths.  Instead 
of  the  many  dying  young,  the  majority  will  survive  to  middle 
life  or  old  age.  The  individual  will  have  a  better  chance  of 
living  what  may  be  said  to  be  a  life  of  "normal"  duration. 

(b)  Unhealthful  regions  of  the  earth  will  be  made  habitable, 
consequently  human  overcrowding  will  be  relieved,  and  more 
of  the  earth's  treasures  will  be  available  for  mankind. 

(c)  The  economic  productiveness  of  the  individual  as  well  as 
of  the  race  will  be  increased.  As  a  consequence  individual  and 
national  wealth  will  increase  and  poverty  and  want  diminish. 

(d)  The  supply  of  animal  foods  will  increase  and  only  be 
limited  b  y  the  available  roughage. 


20  PRACTICAL    PREVENTIVE    MEDICINE 

(e)  Lastly  we  may  prophesy  an  improvement  in  the  general 
physical  condition  of  the  race. 

The  effective  operation  of  the  necessary  machinery  to  apply 
the  etiological  knowledge  we  shall  briefly  sketch  may  be  said 
to  be  the  problem.  It  is  one  of  great  difficulty  and  complexity 
and  its  complete  solution  is  far  distant.  Partial  means  to 
control  the  diseases  of  group  one  are  as  we  shall  presently  see, 
of  considerable  antiquity,  and  arose  from  a  recognition  that 
persons  infected  with  communicable  diseases  were  a  danger  to 
the  public.  Thus  there  developed  the  field  of  public  health. 
Originally  it  arose  from  a  purely  selfish  attitude  on  the  part  of 
society  as  a  whole  to  protect  itself  from  certain  infected  indi- 
viduals, whose  objectionable  characteristics  arose  from  no  fault 
of  their  own.  To-day  we  find  a  changing  attitude,  a  realiza- 
tion that  if  society  requires  protection  by  enforcing  certain 
restrictive  measures  on  individuals  innocent  of  crime,  justice 
demands  that  these  persons  receive  consideration.  In  addition 
the  field  of  public  health  has  recently  come  to  have  a  broader 
scope,  due  to  the  realization  that  many  of  our  problems,  if 
not  all,  have  a  sociological  foundation,  and  that  a  divorce  is 
not  always  possible.  Relief  will  only  be  secured  when  these 
associated  problems  are  solved. 

In  a  general  way  our  problem  of  disease  prevention  has  two 
aspects,  namely  curative  and  prophylactic. 

The  curative  aspect  is  primarily  the  problem  of  the  practic- 
ing physician  and  when  effectively  solved  will  be  manifested 
by  a  lowered  case-mortality.  The  physician  will  be  assisted  in 
its  solution  by  the  development  of  methods  and  the  provision 
of  facilities  for  the  making  of  prompt  diagnoses  and  the  develop- 
ment and  application  of  specific  therapeutic  measures.  This 
aspect  is  clearly  a  problem  of  the  practicing  physician  in  his 
relation  to  the  individual  requiring  his  services. 

On  the  other  hand  the  prophylactic  aspect  can  only  give 
satisfactory  results  when  an  entire  social  unit,  such  as  any 
community,  takes  cognizance  of  its  problem  and  attacks  it 
with  all  the  resources  at  its  collective  command.  For  this  pur- 
pose our  social  and  political  units  have  delegated  power  and 
authority  to  certain  officials  for  the  protection  of  the  public 
health.  The  problem  confronting  the  officials  relates  particu- 
larly to  a  reduction  in  the  number  of  cases  of  preventable 
diseases  in  the  population  under  their  care.  They  are  not  pro- 
fessionally interested  in  disease  from  the  individualistic  stand- 
point of  the  physician.     The  degree  of  success  achieved  by 


INTRODUCTION  21 

these  officials  will  be  directly  in  proportion  to  the  degree  in  which 
they  educate  their  public  in  the  principles  they  are  trying  to 
apply.  Without  the  co-operation  of  the  medical  profession  and 
the  laity  health  authorities  will  accomplish  very  little  effective 
work. 

In  general  the  field  of  public  health  work  may  be  said  to  have 
the  following  scope: 

(a)  Improved  personal  hygiene  of  all  individuals,  including 
better  standards  of  personal  cleanliness,  better  dietaries,  reason- 
able working  hours,  recreation  and  adequate  clothing. 

(b)  Improved  standards  of  domestic  and  public  sanitation, 
including  relief  from  overcrowding,  proper  illumination,  heating 
and  ventilation,  water  supply,  excreta  disposal,  etc. 

(c)  Improved  sanitation  of  places  of  employment. 

id)  The  immunization  of  susceptible  persons  and  the  con- 
trol of  infected  persons. 

(e)  The  improvement  of  the  breeding  stock  of  the  human  race 
by  the  elimination  of  the  physically  and  mentally  unfit  from 
reproduction. 

(/)  The  provision  of  facilities  for  aiding  physicians  in  the 
diagnosis  and  care  of  their  patients,  i.e.,  laboratories,  hospitals 
and  clinics. 

Landmarks  in  the  Development  of  Preventive  Medicine. — 
The  only  practices  of  the  ancients  which  we  at  this  day  may 
consider  to  be  preventive  measures  based  upon  a  firm,  rational 
foundation  as  we  understand  the  subject,  are  found  described 
in  the  Mosaic  law.  All  other  practices  of  the  ancients  designed 
to  prevent  diseases  are  clearly  allied  with  religion  and  super- 
stition, and  hence  were  of  little  importance  and  no  value. 
Therefore  the  Mosaic  instructions  when  interpreted  in  the 
light  of  present  day  knowledge  have  an  immense  importance. 
These  practices  however  do  not  seem  to  have  been  copied  by 
contemporaneous  Gentile  races. 

Aside  from  the  foregoing  the  earliest  public  health  practice 
which  has  survived  to  the  present  day  is  maritime  quarantine, 
which  was  developed  by  the  mediaeval  Italian  cities  of  Venice 
and  Genoa  when  at  the  height  of  their  commercial  splendor, 
as  a  protection  against  the  introduction  of  plague  from  oriental 
ports.  At  this  time  the  ideas  of  disease  transmission  were  very 
vague,  but  a  suspicion  of  the  transmissibility  of  some  seems  to 
have  existed.  A  little  later,  in  1546,  Geronimo  Fracastorius 
published  in  Venice  a  work  entitled  "De  contagionibus  et  con- 
tagiosis  morbis  et  curatione"  in  which  was  first  definitely  ad- 


2  2  PRACTICAL    PREVENTIVE    MEDICINE 

vanced  the  doctrine  of  contagion.  He  divided  infections  into 
three  classes:  (i)  Those  infecting  by  immediate  contact,  (2) 
Those  infecting  through  intermediate  agents,  such  as  fomites 
and  (3)  Those  infecting  at  a  distance  or  through  the  air  In 
1659  Kircher,  and  in  1675  van  Leeuwenhoek  first  observed  and 
described  living  organisms  too  small  to  be  seen  by  the  naked 
eye.  Kircher  in  1671  suggested  that  various  infections  were  the 
result  of  the  activity  of  these  minute  organisms.  Kircher's 
views  were  received  with  scepticism  by  his  contemporaries,  and 
later,  in  1762,  Plenciz  of  Vienna  again  advanced  the  same 
views.  These  theories  however  did  not  gain  headway  until  the 
following  century,  when  they  were  demonstrated  scientifically. 

The  first  attempt  at  artificial  active  immunization  among  Euro- 
pean nations  must  be  credited  to  Lady  Mary  Wortley  Montague, 
who  from  1717  to  1721  introduced  into  England  from  Constan- 
tinople, the  process  of  variolation  as  a  protection  against  small- 
pox. This  was  an  event  whose  importance  has  been  over- 
shadowed by  the  employment  of  an  attenuated  virus  for  the 
same  purpose  by  Jenner.  His  discovery  was  first  published  in 
1798. 

In  1843,  Oliver  Wendell  Holmes,  an  American  physician  and 
author  of  note,  first  called  attention  to  the  contagiousness  of 
puerperal  fever.  The  activity  of  water  as  a  route  for  the  trans- 
fer for  infective  agents  was  first  recognized  in  1854  by  Dr. 
Snow  in  connection  with  the  famous  Broad  Street  well  cholera 
outbreak.  Three  years  later,  Dr.  Taylor  recognized  the  simi- 
lar activity  of  milk  in  an  outbreak  of  typhoid  at  Penrith.  The 
first  scientific  demonstration  of  the  transmissible  character  of 
an  infectious  disease  was  performed  by  Villemin  with  tuber- 
culosis in  1865,  while  the  first  demonstration  of  the  etiological 
relation  of  micro-parasites  to  disease  was  accomplished  by 
Pasteur  in  the  case  of  anthrax  in  1876,  thus  substantiating  the 
earlier  beliefs  of  Kircher  and  Plenciz.  Patrick  Manson  rec- 
ognized the  first  known  insect  transmitted  disease,  when  he 
found  that  mosquitoes  transmit  Filaria  bancrofti. 

From  the  time  of  Jenner  no  progress  in  artificial  immunization 
was  made  until  Pasteur  demonstrated  the  protective  power  of 
his  anthrax  vaccine  on  sheep  in  1881,  and  in  1885  extended  the 
same  principle  to  the  treatment  of  rabies. 

In  1893,  Smith  and  Kilbourne,  two  Americans,  discovered 
the  cause  and  means  of  transmission  of  the  first  known  insect 
transmitted  protozoal  disease,  namely  Texas  fever  of  cattle. 

The  importance  of  carriers  in  the  perpetuation  of  typhoid 


INTRODUCTION 


23 


fever  was  first  recognized  by  Robert  Koch,  who  called  attention 
to  them  in  1902.  Carriers  of  the  diphtheria  bacillus  had  been 
observed  before  this,  but  their  importance  was  not  recognized. 
The  results  which  can  accompany  the  application  of  the 
principles  of  preventive  medicine  received  their  first  great 
popular  demonstration  by  Gorgas,  when  he  eradicated  yellow 
fever  and  malaria  from  Havana  and  the  Canal  Zone.  This 
accomplishment  may  be  considered  to  mark  the  beginning  of 
active  public  interest  in  the  possibilities  of  preventive  medicine, 
a  situation  which  may  be  said  to  characterize  the  present  day. 

REFERENCES 

Sedgwick:  Principles  of  Sanitary  Science  and  the  Public  Health.     Chapters 
II,  III,  IV. 

Leviticus — Chapter  XIII:  14 
Deuteronomy — Chapter  XXIII :  1 3 
Eager:  The  Early  History  of  Quarantine. 

Yellow  Fever  Institute  Bull.  No.  12,  U.S.P.H.  and  M.H.  Service. 
Mortality  Statistics.     Published  annually  by  the  Bureau  of  Census  since 
1900. 


SECTION  I 

DISEASES  DUE  TO  INVADING  MICRO- 
ORGANISMS: EPIDEMIOLOGY 

CHAPTER  II 
SOURCES  OF  INFECTION 

i.  As  a  result  of  the  invasion  of  a  population  by  a  given 
species  of  pathogenic  micro-organisms  certain  phenomena  are 
produced,  some  of  which  are  of  present  interest,  particularly 
those  dealing  with  the  incidence  or  prevalence  of  disease.  This 
constitutes  the  field  of  epidemiology,  which  may  be  defined 
as  the  science  treating  of  the  sources  and  routes  of  infection 
and  their  activities,  as  manifested  by  the  incidence  or  prevalence 
of  an  infectious  disease  in  a  given  population. 

2.  Before  proceeding  further  certain  fundamental  definitions 
had  best  be  presented: 

(a)  An  infectious  disease  is  produced  as  the  result  of  the 
invasion  of  the  tissues  of  an  animal  or  plant  by  a  living  organism. 
Because  the  invading  organism  may  be  in  many  instances 
transferred  from  individual  to  individual  of  the  host  species, 
these  diseases  are  perhaps  more  aptly  termed  communicable. 
Those  communicable  diseases  which  are  transmitted  exclusively 
or  nearly  so,  directly  from  host  to  host  are  spoken  of  as  con- 
tagious, or  popularly  as  "catching." 

(b)  Following  the  invasion  of  the  host  by  an  organism  capable 
of  producing  disease,  a  variable  period  elapses  before  the  char- 
acteristic symptoms  are  manifested  and  during  which  the 
ordinary  health  is  apparently  maintained.  This  period  is  the 
incubation  period.  With  some  infections,  as  small  pox  and 
measles,  its  length  is  very  constant,  with  others  such  as  typhoid, 
it  is  subject  to  considerable  variation.  Its  duration  is  probably 
dependent  upon  the  number  and  virulence  of  the  invading 
organisms  on  the  one  hand,  and  to  the  specific  degree  of  the 
host's  resistance  on  the  other. 

(c)  A  primary  case  of  a  communicable  disease  is  the  first 
case  arising  within  a  given  area,  which  is  the  ascribed  source 

24 


SOURCES    OF   INFECTION  25 

of  the  infective  agents  transferred  to  other  individuals  who 
later  develop  the  same  infection. 

A  secondary  case  of  a  communicable  disease  arises  as  a  result 
of  infection  received  from  a  pre-existing  known  case,  with 
which  it  has  been  associated.     Both  are  relative  terms. 

A  vector  is  any  intermediate  object  which  serves  to  transfer 
infective  agents  from  one  host  to  another.  The  use  of  this 
term  is  commonly  restricted  to  those  insects  which  occupy  this 
position. 

An  epidemic  is  the  occurrence  within  a  limited  time  among  a 
limited  population,  of  an  unusual  number  of  cases  of  communi- 
cable disease. 

A  pandemic  is  similar  to  an  epidemic,  except  the  population 
concerned  is  much  larger,  that  of  an  entire  continent  or  the 
world. 

Endemic  refers  to  the  usual  prevalence  of  a  communicable 
disease  among  a  limited  population. 

Epizootic  is  a  term  analagous  to  epidemic,  referring  to  the 
diseases  of  lower  animals. 

3.  Sources  of  Infection. — As  a  result  of  extensive  bacterio- 
logic  researches  as  well  as  epidemiologic  studies  of  similar  magni- 
tude, performed  by  scientific  observers  everywhere  it  may  be 
stated  as  axiomatic  that: 

All  communicable  diseases  arise  from  the  invasion  of  a  sus- 
ceptible host  by  organisms  derived  from  a  pre-existing  invaded 
host.  The  pre-existing  invaded  host  is  known  as  the  source 
of  infection. 

It  has  long  been  observed  as  a  fairly  constant  characteristic 
that  a  greater  incidence  of  these  diseases  was  found  among  in- 
dividuals in  contact  with  those  sick  with  the  same  disease, 
although  many  cases  certainly  occur  that  do  not  present  such  a 
history.  At  one  time  in  the  early  days  of  bacteriologic  science 
it  was  believed  that  patients  had  received  infection  from 
organisms  that  had  developed  in,  and  were  received  from  a 
patient's  environment.  In  other  words,  the  invaders  were 
saprophytes  which  incidentally  possessed  pathogenic  powers. 
Such  is  apparently  the  actual  case  with  some  of  the  patho- 
genic fungi.  On  the  other  hand,  the  pathogenic  bacteria  are 
apparently  of  a  highly  parasitic  nature.  Bacteriological 
researches  have  failed  to  demonstrate  that  they  can  live  a 
sustained  vegetative  extracorporeal  existence.  When  found 
without  the  body  it  is  under  circumstances  which  indicate  they 
are  existing  within  a  definite  radius  surrounding  an  infected 


26  PRACTICAL   PREVENTIVE   MEDICINE 

person,  and  their  origin  has  been  undeniably  the  excretions  and 
secretions  of  the  infected  person,  and  it  has  been  further  found 
that  these  micro-organisms,  with  certain  few  notable  exceptions, 
are  only  capable  of  a  rather  transitory  extracorporeal  existence, 
during  which  period  their  vital  activities  are  more  or  less  sus- 
pended and  their  vitality  tends  to  decrease. 

4.  The  sources  of  infection  as  defined  above  may  be  classified 
as  follows: 

(a)  Typical  Cases. — These  are  individuals  in  whom  the  dis- 
ease presents  the  clinical  manifestations  typical  of  the  disease. 

(b)  Atypical  Cases  (Abortive  or  Missed). — These  are  indi- 
viduals in  whom  the  clinical  symptoms  are  indefinite  or  indistinc- 
tive, and  as  a  consequence  are  difficult  to  diagnose.  Furthermore 
the  illness  is  usually  mild.  Bacteriologic  assistance  is  fre- 
quently required  for  a  diagnosis,  though  sometimes,  when 
occurring  as  secondary  cases  where  the  primary  case  is  known, 
they  may  be  diagnosed  clinically.  Their  proportion  to  the 
typical  cases  varies  with  different  diseases. 

(c)  Carriers  are  apparently  healthy  persons  who  are  harboring 
the  specific  organisms  of  communicable  diseases  and  discharging 
them  from  their  bodies.  They  are  encountered  in  well  defined 
types. 

1.  Incubatory  carriers,  i.e.,  individuals  who  are  actually 
in  the  incubation  period  of  a  given  infectious  disease  and  will 
shortly  manifest  the  characteristic  symptoms. 

2.  Healthy  carriers,  i.e.,  individuals  who  throughout  the 
entire  period  of  their  harborage  never  present  clinical  mani- 
festations that  may  be  referable  to  their  parasitism. 

3.  Convalescent  carriers,  i.e.,  individuals  who  have  recovered 
from  an  attack  of  the  disease  in  question,  but  who  continue  to 
harbor  the  specific  infective  agents.  According  to  the  dura- 
tion of  their  infectivity,  convalescent  carriers  are  commonly 
arbitrarily  divided  into  two  groups: 

(a)  Temporary  carriers,  whose  infectivity  subsides  in  three 
months  following  the  development  of  their  convalescence,  and 

(b)  Chronic  carriers,  in  whom  the  infective  agents  persist  for 
periods  longer  than  three  months. 

It  must  be  remembered  that  the  healthy  and  convalescent 
carriers  possess  an  active  resistance  to  the  micro-organisms  they 
are  harboring,  so  that  while  they  themselves  are  protected 
they  endanger  their  associates. 

The  proportion  of  carriers  to  cases  at  any  given  time  with  a 
given  disease  is  subject  to  wide  fluctuations  and  is  difficult  of 


SOURCES    OF   INFECTION  27 

accurate  estimation.  The  carrier  condition,  in  so  far  as  it  re- 
lates to  the  actual  discharge  of  micro-organism  is  intermittent. 
The  particular  secretions  or  excretions  are  not  continuously 
infective,  even  though  the  micro-organisms  are  continually 
present  in  the  body.  In  this  respect  the  carrier  condition  is 
closely  related  to  the  group  of  sources  known  as  latent  cases. 

(d)  Latent  Cases. — With  certain  infections  the  active  clinical 
manifestations  tend  to  spontaneously  subside,  though  the  micro- 
organisms themselves  persist,  apparently  in  a  latent  condition, 
for  long  and  variable  periods  of  time,  later  to  renew  their  ac- 
tivity when  from  some  intercurrent  cause  their  host's  resistance 
is  reduced.  During  the  period  of  their  latency  they  are  not 
discharged  from  the  body.  Latent  infection,  for  example,  is 
observed  in  syphilis,  tuberculosis  and  glanders. 

(e)  Lower  Animals  as  Sources  of  Infection. — The  foregoing 
observations  relate  particularly  to  the  so-called  diseases  of  man, 
for  which  human  beings  serve  solely  as  sources  of  dissemination. 
On  the  other  hand,  a  certain  group  of  human  infections,  such 
as  rabies,  glanders,  anthrax,  etc.,  are  not  due  to  agents  derived 
from  infected  human  beings,  but  from  infected  animals,  though 
the  role  for  the  animal  as  a  source  of  infection  is  closely  parallel. 

5.  Examples  of  disease  classification  in  the  foregoing  types: 

(a)  Atypical  forms  are  encountered  in  the  following  infections : 

Typhoid  fever  Poliomyelitis 

Septic  sore  throat  Typhus  Fever 

Measles  Diphtheria 

Asiatic  cholera  Small  pox 

Meningococcus  meningitis  Yellow  fever 
Scarlet  fever 

(b)  Incubatory  carriers  have  been  observed  in  the  following: 

Typhoid  Fever  Whooping  cough 

Paratyphoid  Fever  Measles 

Malta  Fever  Small  pox 

Dysentery  (amoebic)  Anthrax 
Diphtheria 

(c)  Healthy  carriers  of  micro-organisms  producing  the  fol- 
lowing diseases  have  been  observed: 

Typhoid  Fever  Pneumonia 

Paratyphoid  Fever  Meningococcus  meningitis 

Dysentery    (amoebic  and      Gonorrhoea 
bacillary)  Plague 


28  PRACTICAL   PREVENTIVE   MEDICINE 

Cholera  Poliomyelitis 

Diphtheria  Malaria 

Scarlet  Fever 

(d)  Convalescent  carriers  of  the  following: 

Typhoid  Fever  Dysentery      (bacillary      and 

Paratyphoid  Fever  amoebic) 

Diphtheria  Cholera 

Pneumonia  Meningococcus  meningitis 

Poliomyelitis  African  Sleeping  Sickness 

6.  Exit    of    Micro-organisms    from    the   Body    of    Infected 
Persons. 

Different  species  of  micro-crganisms  have  adapted  them- 
selves to  different  pathways  of  exit  from  the  body  of  infected 
persons.  In  order  that  the  propagation  of  the  species  be  main- 
tained, it  is  of  course  necessary  that  colonizing  individuals  be 
disseminated.  For  the  most  part  the  adaptation  is  to  the 
natural  avenues  of  exit  used  for  the  physiological  discharge  of 
surplus  secretions  or  the  excretions  of  the  body.  To  a  consider- 
able extent  the  adaptation  is  specific,  i.e.,  certain  of  these  path- 
ways are  more  certain  to  contain  micro-organisms  producing  a 
given  disease,  than  others.  For  example  the  following  dis- 
charges are  the  means  of  exit  of  the  infective  agents  producing: 

(a)  Feces:  Typhoid,  dysentery,  cholera,  etc. 

(b)  Urine:  Typhoid,  etc. 

(c)  Sputum:  Tuberculosis,  pneumonia,  etc. 

(d)  Saliva:  Rabies. 

(e)  Nasopharyngeal  -secretions:     Diphtheria,  cerebro-spinal 
meningitis,  etc. 

(/")  Sweat:  Typhoid. 

(g)  Milk:  Typhoid,  Malta  fever,  tuberculosis. 

Qi)  Epithelial  desquamations:  Small  pox. 

{i)  Purulent  discharges:  Scarlet  Fever. 

(j)  Blood :  Malaria,  African  sleeping  sickness. 

(k)  Lachrymal    secretion:  Conjunctivitis. 

(/)  Placental  circulation:  Syphilis,  tuberculosis. 

REFERENCES 

Chapin:  Sources  and  Modes  of  Infection.     Chapter  II. 

Ledingham  and  Arkwright:  The  Carrier  Problem  in  Infectious  Disease. 

Simon:  Human  Infection  Carriers. 

Rosenau:  Preventive  Medicine  and  Hygiene.     Chapter  VII,  pp.  362. 


CHAPTER  III 
THE  DISSEMINATION  OF  INFECTIVE  AGENTS 

i.  Stage    of    Disease    in    Relation    to    Dissemination. — (a) 

Stage  of  Invasion  and  Incipiency. — With  some  diseases 
such  as  tuberculosis,  when  the  micro-organisms  are  in  deep- 
seated  lesions  not  in  contact  with  passage  ways  to  the  exterior, 
the  infected  person  is  of  little  or  no  active  danger  to  others 
as  a  source  of  infection.  On  the  other  hand,  with  diseases 
such  as  diphtheria,  where  the  micro-organisms  are  in  superficial 
situations  having  ready  access  to  the  exterior,  this  period  is  of 
great  importance. 

(b)  Non-infective  Stages  of  Active  Disease. — When  syphilitic 
infection  progresses  to  the  tertiary  and  para-syphilitic  stages, 
these  as  long  as  they  persist  are  non-infectious.  On  the  other 
hand,  they  partake  of  the  character  of  latent  infections,  inas- 
much as  relapses  to  lesions  of  the  secondary  type  may  occur. 

2 .  Portals  Through  Which  Infective  Agents  Enter  the  Body. — 
Different  infective  agents  have  adapted  themselves  to  varying 
portals  of  entrance  into  the  body  and  for  the  most  part,  if 
introduced  by  a  route  other  than  the  one  to  which  adapted, 
fail  to  gain  a  foothold.  The  principal  body  orifices  again  play 
an  important  part,  particularly  the  orifices  of  entrance,  rather 
than  those  of  exit.  After  having  passed  the  threshold  of  this 
portal,  the  infective  agents  may  proceed  by  divergent  pathways 
to  penetrate  the  physiological  interior  of  the  body. 

The  mouth  and  the  nose  are  portals  of  entrance  of  greatest 
importance  from  the  standpoint  of  the  number  of  infective 
agents  which  are  introduced  through  them. 

After  passing  this  threshold,  some,  as  the  typhoid  bacillus 
may  go  onward  to  the  intestinal  tract,  others  as  the  pneumo- 
coccus  procede  to  the  respiratory  passages,  while  others  as  the 
diphtheria  bacillus,  will  remain  near  the  point  of  their  entry  in 
the  naso-pharynx. 

Areas  of  specialized  epithelium,  as  for  example  that  of  the 
conjunctiva  or  genitalia,  are  particularly  well  suited  to  some 
infective    agents. 

29 


3° 


PRACTICAL   PREVENTIVE   MEDICINE 


Others,  by  various  means,  usually  due  to  some  form  of 
traumatism,  (inoculation)  directly  penetrate  the  outer  epithe- 
lium of  the  body  to  the  subcutaneous  tissues,  and  thence  gain 
access  to  the  circulation  or  to  the  central  nervous  system. 

3.  Dosage. — The  mere  introduction  of  a  given  infective 
agent  into  the  body  will  not  necessarily  mean  that  the  micro- 
organisms will  succeed  in  gaining  a  foot-hold.  The  success 
of  a  given  transfer  will  vary  directly  with  the  number  and 
virulence  of  the  organisms  transferred,  and  indirectly  with  the 
resistance  of  the  individual  invaded.  These  factors  also  in- 
fluence the  duration  of  the  period  of  incubation. 

4.  The  Extracorporeal  Existence  of  Infective  Agents. — The 
infective  agents  are  for  the  most  part  highly  specialized  para- 
sites that  require  for  their  existence  the  conditions  of  tempera- 
ture, humidity,  moisture,  and  nutrition  that  they  encounter 
within  the  body  of  their  host.  When  these  conditions  are  not 
available  their  vegetative  and  reproductive  activities  become 
sluggish,  and  if  prolonged  the  vitality  of  the  organism  may 
become  impaired.  Furthermore  the  colonizing  individuals 
when  expelled  from  the  body  of  their  host  are  ordinarily  imme- 
diately exposed  to  the  action  of  the  natural  germicidal  agencies, 
sunlight  and  desiccation.  (See  Table  II.)  In  consequence  of 
these  factors  they  become  rapidly  attenuated  and  are  soon 


TABLE  II 

Resistance  to  Sunlight  and  Desiccation  of  certain  non-spore  forming  Bacteria. 

(Compiled  from  various  authorities) 


Organism 

Sunlight  direct 

Material 

Authority 

Sp.  pallida 

Diffuse — II>2  nrs- 

Cultures 

Zinsser 

Gonococcus 

Pneumococcus 

i  hr. 

Hiss  &  Zinsser 

Meningococcus 

Less  than  24  hrs. 

Hiss  &  Zinsser 

B.  mallei 

24  hrs. 

Hiss  &  Zinsser 

Cholera  vibrio 

B.  pestis 

4-5  hrs. 
6  min. 

film  culture 

Hiss  &  Zinsser 

B.  diphtheria; 

Briscoe 

B.  typhosus 

9-26  hrs. 

fabric 

Sternberg 

2  min. 

fabric 

Briscoe 

B.  tuberculosis 

2  min. 

fabric 

Briscoe 

45  nrs. 

sputum 

Mitchell  &  Crouch 

M.  melitensis 

THE    DISSEMINATION    OP    INFECTIVE    AGENTS 


31 


Organism 


Desiccation 


Material 


Authority 


Xotes 


Sp.  pallida 

1  hr. 

Films 

Zinsser 

Gonococcus 

18-24  hrs. 

Pus  on  fabrics 

Hiss  &  Zinsser  1 

Pneumococcus 

1-4  mo.  no 

• 

Hiss  &  Zinsser;  In  fine  spray  spu- 

light 

turn,   3*2  hrs.,  ordi- 
nary     light       and 

temperature-Wood. 

Meningococ- 

3 hrs— 2o°C. 

Besson 

cus 

B.  mallei 

48  hrs.-room 
temp. 

Pus,  thin  layer 

Besson 

Cholera  vibrio 

1  min. 

Film 

Strong 

Dry  atmosphere,  6 
min.,  spray  wet  at- 
mosphere 30  min. 
in  spray.    Strong. 

B.  pestis 

5  min. 

Film 

Strong 

Floors — 24-48  hrs. 
Adv.  Comm.  India. 

B.  diphtherise 

5  days . 

Film 

Briscoe 

Desiccated  in  mem- 
brane— 4  mos. 
still  virulent 

Park  &  Williams. 

B. typhosus 

5  days 

Film 

Briscoe 

B.  tuberculosis 

8  days 

Film 

Briscoe 

2  mos. 

Sputum 

Hiss  &  Zinsser 

M.  melitensis 

13-28  days 

Dust 

Med.  Fever 
Com. 

7-37  days 

Fabric  &  Urine 

Med.   Fever 
Com. 

Note:  Results  refer  to  action  of  the  full  physical  force  concerned. 


destroyed.  It  is  exceedingly  rare  for  them  to  gain  introduction 
into  any  medium  favorable  for  multiplication,  such  as  milk. 
The  fortunate  individuals  who  do  succeed  in  reaching  a  new 
host  are  but  a  small  fraction  of  those  which  left  the  source. 
These  circumstances  are  our  salvation. 

It  must  of  course  be  remembered  that  the  spore-forming 
bacteria  such  as  the  anthrax  and  tetanus  bacilli,  are  exceptions 
to  the  rule  in  so  far  as  survival  is  concerned,  but  on  the  other 
hand,  their  numbers  probably  do  not  increase  during  this  period. 

Exception  must  also  be  made  to  certain  animal  infective 
agents.  These  which  have  a  definitive  host  of  course  multiply 
in  that  species.  A  few  of  the  multicellular  parasites  require 
an  extracorporeal  period  to  complete  certain  stages  of  their 
life  cycle  and  are  particularly  adapted  to  this.     Their  degree  of 


32  PRACTICAL    PREVENTIVE    MEDICINE 

specialization  as  parasites  is  rot  as  extreme  as  it  is  with  the 
parasitic  bacteria. 

Therefore  as  a  general  rule,  the  closer  the  relationship  in  time 
and  space  with  the  source  oj  infection,  the  greater  is  the  chance 
or  the  successful  transfer  of  unattenuated  infective  agents. 

5.  Routes  of  Transference. — The  successful  transfer  of  in- 
fective agents  from  host  to  host  is  a  lottery  in  which  all  the 
chances  are  against  the  individual  micro-organisms.  The 
perpetuation  of  the  species  is  secured  by  the  discharge  of  tre- 
mendously enormous  numbers  of  individuals  from  the  infected 
source. 

Their  transfer  is  effected  by  means  which  serve  unconsciously 
to  carry  human  secretions  from  one  person  to  another.  These 
means  may  be  classified  into  the  following  groups  in  order  of 
their  importance.     They  are: 

(a)  Contact 

(b)  Foods,  including 
Water  and  Ice. 

Milk  and  Dairy  Products. 
Meat  and  Shell  fish. 
Other  Foods. 

(c)  Insects 

Mechanical  transmission. 
Biological  transmission. 

(d)  Soil. 

{e)  Fomites. 

By  the  later  term  we  understand  objects  upon  which  infective 
agents  may  retain  their  vitality  for  prolonged  periods  of  time. 
As  a  matter  of  fact,  this  means  of  transmission  is  closely  related 
to  certain  forms  of  contact  and  is  only  of  importance  with  the 
spore-forming  infective  agents. 


CHAPTER  IV 
CONTACT  TRANSMISSION 

i.  By  contact  transmission  we  mean  the  transfer  of  infective 
secretions  or  excretions  from  one  person  to  another  with  the 
lapse  of  but  a  short  space  of  time  during  which  interval  the  in- 
fective agents  are  subject  to  little  or  no  attenuation.  From 
the  great  variety  of  infective  agents  transmitted  by  this  means, 
as  well  as  the  constancy  with  which  opportunities  for  this 
transference  are  encountered,  it  is  the  most  important  of  the 
routes  of  infection. 

2.  Means  of  Contact  Transference. — Briefly  we  may  say 
that  contact  transmission  is  accomplished  through  the  con- 
tinous  universal  commerce  in  the  body  secretions  and  excre- 
tions. This  commerce  is  accomplished  by  the  following 
agencies. 

(a)  Mouth  Spray  or  Droplet  Infection. — Every  person  in 
talking,  coughing,  or  sneezing,  emits  from  the  mouth  with  more 
or  less  explosive  force  a  fine  spray  of  saliva,  which  will  of  course 
contain  suspended  in  it,  micro-organisms  from  the  mouth, 
nasopharynx,  or  respiratory  passages.  These  particles  remain 
suspended  in  the  air  for  some  time  by  reason  of  their  buoyancy, 
but  tend  to  settle  out.  Air  currents  may  distribute  them  for 
short  distances.  They  will  of  course  ultimately  evaporate  and 
with  evaporation,  desiccation  of  the  micro-organisms  will  occur. 
The  survival  of  the  droplets  will  of  course  be  longer  in  a  cold 
humid  atmosphere  than  in  a  warm  dry  atmosphere.  In  a  more 
or  less  stagnant  atmosphere,  a  quiescent  individual  may  cover 
a  radius  of  about  six  feet  with  these  droplets.  These  are  prob- 
ably of  greatest  importance  when  expelled  directly  onto  the 
body  surface  of  another  individual,  although  the  buoyant 
particles  are  undoubtedly  responsible  for  the  old  belief  in  air- 
borne infection. 

(b)  Hands  and  Fingers  contaminated  with  Secretions  are 
undoubtedly  the  most  important  agencies  in  contact  infection. 
Their  importance  is  both  from  the  standpoint  of  distribution 
and  collection.  Fingers  are  naturally  exploratory  in  their 
habits,  reaching  all  portions  of  the  body  surface  and  the  body 

3  33 


34  PRACTICAL   PREVENTIVE    MEDICINE 

orifices  of  their  owner,  thus  becoming  contaminated  with  the 
secretions  and  excretions,  and  transferring  these  to  objects  later 
handled. 

In  turn  from  such  objects,  the  infective  secretions  of  other 
persons  similarly  distributed,  are  collected  and  introduced 
into  or  onto  the  body  of  their  owner.  The  ringers  of  a  non- 
infected  person  may  also  transfer  infective  agents  to  a  third 
person.  It  is  for  this  reason  that  the  habits  of  avoiding  the 
unnecessary  introduction  of  the  fingers  into  the  mouth  and 
nose,  as  well  as  the  habit  of  washing  the  hands  before  eating, 
are  of  paramount  hygienic  importance. 

(c)  A  certain  communism  in  small  objects  was  formerly 
very  popular,  but  fortunately  today  is  looked  upon  with  little 
esteem.  This  was  the  practice  of  furnishing  common  articles 
in  public  places  for  intimate  personal  service,  such  as  drinking 
cups,  towels,  combs,  pencils  and  numerous  other  objects.  The 
intimate  use  to  which  these  are  put  renders  their  contamination 
by  excretions  and  secretions  practically  unavoidable,  which  will 
be  effectively  transferred  to  the  next  person  using  them.  Des- 
pite the  reduction  in  recent  years  of  objects,  such  as  drinking 
cups,  which  are  directly  contaminated  with  secretions,  it  is  prac- 
tically impossible  to  always  avoid  objects  which  are  continually 
contaminated  with  human  secretions. 

(d)  Lastly,  direct  approximation  of  the  body  surfaces  of  two 
different  individuals,  such  as  that  which  occurs  during  a  hand 
clasp,  kissing  or  sexual  intercourse,  will  effectively  transmit 
infective  agents  present  on  one  to  the  other,  under  circum- 
stances which  of  course  are  altogether  favorable  to  the  infective 
agents. 

The  term  direct  contact  transmission  is  applied  to  the 
second  and  the  last  of  these  agencies,  as  well  as  to  certain  aspects 
of  the  first.  In  these  of  course,  no  intermediate  objects  par- 
ticipate in  the  transfer.  Distinction  between  indirect  contact 
transmission  and  fomites  transmission  has  already  been  made. 

3.  Importance  of  Contact  Transmission  with  Different  Infec- 
tive Agents. — According  to  the  importance  of  contact  in  the 
transmission  of  different  infective  agents,  we  can  distinguish 
several  groups  of  diseases. 

(a)  Diseases  Transmitted  Solely  by  Direct  Contact. — This 
group  includes  the  venereal  diseases,  syphilis  and  gonorrhoea, 
which  from  a  practical  standpoint  are  propagated  nearly  ex- 
clusively by  sexual  intercourse.  Under  these  circumstances 
fresh  highly  infective  secretions  are  transferred. 


CONTACT   TRANSMISSION  35 

(&)  Diseases  Usually  Transmitted  by  Contact. — This  group 
includes  the  common  so-called  "  contagious "  diseases,  for 
example,  small  pox,  chicken  pox,  mumps,  whooping  cough, 
measles,  diphtheria,  scarlet  fever,  common  colds,  influenza, 
tuberculosis,  meningitis,  pneumonia,  poliomyelitis,  etc.  It  is 
known  that  several  of  these  may  be  transmitted  by  other  routes 
of  infection,  but  with  all  contact  transmission  is  the  principle 
means  by  which  the  infective  agents  are  distributed. 

(c)  Diseases  Frequently  Transmitted  by  Contact. — With  these 
contact  transmission  is  quite  common  and  is  of  far  greater 
importance  in  the  propagation  of  their  infective  agents  than  is 
generally  recognized.  The  spectacular,  explosive  outbreaks  due 
to  the  occasional  activity  of  other  routes  of  infection  have 
overshadowed  the  quiet  unpretentious  activity  of  contact  in  the 
continued  propagation  of  their  infective  agents.  To  this  group 
belong  typhoid  fever,  Asiatic  cholera  and  dysentery  (Fig.  3). 

4.  It  is  to  be  noted  in  the  foregoing  classification  that  the 
varying  importance  of  contact  transmission  is  clearly  associated 
with  the  route  of  exit  from  the  body  to  which  different  species 
of  infective  agents  are  adapted.  As  we  shall  endeavor  to  show, 
this  naturally  influences  the  distribution  of  the  infective  agents. 

In  the  first  of  the  foregoing  groups,  namely  the  venereal 
diseases,  the  active  lesions  are  ordinarily  present  on  concealed 
portions  of  the  body,  on  areas  covered  by  the  clothing  which 
tend  to  prevent  the  very  general  distribution  of  infective  secre- 
tions. Transfer  of  the  infective  secretions  comes  as  the  result 
of  an  act,  usually  voluntary,  which  places  two  individuals  in 
such  relationship  that  transfer  of  the  infective  secretions  is 
rendered  not  only  possible  but  probable. 

In  the  second  of  the  above  groups  it  will  be  later  learned  that 
the  most  unusual  avenue  of  exit  selected  by  these  micro- 
organisms, at  least  the  predominating  avenue,  is  that  offered 
by  the  secretions  and  excretions  leaving  by  the  mouth  and  nose. 
The  physiological  structure  of  this  region  is  such  that  these 
secretions  do  not  accumulate  until  of  considerable  volume,  but 
rather  the  accumulations  are  small  and  are  expelled  at  frequent 
intervals.  Furthermore  these  orifices  are  not  covered  by  arti- 
ficial devices,  so  there  is  no  impediment  to  the  frequent  expul- 
sion of  these  secretions,  neither  do  any  motives  of  modesty  or 
artificial  impediments  prevent  the  introduction  of  the  fingers 
into  either  the  mouth  or  the  nose.  As  a  consequence  these 
secretions  are  distributed  thinly  over  a  radius  corresponding 
to  the  daily  movements  of  their  producer. 


36  PRACTICAL   PREVENTIVE    MEDICINE 

In  the  third  group  the  infective  agents  chiefly  leave  the  body 
in  either  the  feces  or  the  urine,  or  both.  These  excretions  are 
not  expelled  continuously  but  accumulate  until  the  capacity 
of  either  the  rectum  or  bladder  is  reached;  thereupon  they  are 
expelled.  Furthermore,  from  considerations  of  modesty  these 
orifices  are  protected  by  the  clothing,  which  reduces  the  fre- 
quency of  finger  contamination  with  these  excretions,  as  well 
as  the  frequency  with  which  these  discharges  are  voided.  As  a 
consequence  these  excretions  are  distributed  thickly  but  irregu- 
larly over  a  relatively  small  radius. 

5.  Importance  of  the  Different  Types  of  Sources  of  Infection 
in  Contact  Transmission. — The  known  cases  are  usually  of 
minor  importance  in  the  propagation  of  these  diseases  for  several 
reasons.  As  a  result  of  the  invasion  they  feel  ill,  consult  a 
physician  who  usually  recognizes  the  infective  character  of 
their  illness  and  directs  that  a  more  or  less  effective  regimen  of 
isolation  be  observed.  Even  in  the  absence  of  a  physician,  the 
severity  of  their  illness  will  tend  to  restrict  their  movements  or 
the  radius  of  their  activities,  and  hence  temporarily  reduce  the 
number  of  their  associates.  Both  of  these  factors  materially 
reduce  the  importance  of  these  patients  in  the  further  propaga- 
tion of  their  infection,  unless  perchance  they  become  convales- 
cent carriers. 

On  the  other  h'and  the  unrecognized  infected  persons  are 
commonly  those  who  experience  little  or  no  inconvenience  as  a 
result  of  the  infection.  As  a  consequence  the  radius  of  their 
activities  is  reduced  but  little,  they  rarely  consult  a  physician, 
their  infectivity  is  seldom  recognized  and  hence  no  precau- 
tionary measures  are  employed.  Their  infective  secretions  are 
as  a  consequence  scattered  over  a  wide  radius.  Thus  they  are 
of  major  importance  in  the  propagation  of  infective  agents. 

It  is  therefore  apparent  the  measures  of  isolation  directed 
against  the  sources  of  infection  will  be  successful  in  inverse 
proportion  to  the  number  of  unrecognized  infected  persons 
at  large  in  a  community. 

6.  Features  Characteristic  of  Contact  Transmission. — {a) 
The  greater  the  intimacy  of  association  between  human  beings, 
the  better  and  more  frequent  will  be  the  opportunities  for  the 
transfer  of  infective  agents  by  contact.  The  incidence  of  con- 
tact disease  is  commonly  in  direct  proportion  to  the  density 
of  population  in  a  given  area. 

(b)  The  intimate  association  of  people  at  home,  at  school  or 
in  different  institutions  favors  the  spread  of  infection  by  con- 


CONTACT    TRANSMISSION 


37 


tact.  This  aspect  is  closely  associated  with  housing  problems, 
with  over-crowding  and  inadequate  lighting  and  ventilation,  both 
of  which  tend  to  prolong  the  vitality  of  pathogenic  micro-organ- 
isms outside  the  body.  Fig.  i  illustrates  housing  conditions 
intensified  by  overcrowding,  that  favor  the  dissemination  of 
infective  agents  by  contact.  Fig.  2  illustrates  the  definite  rela- 
tion of  overcrowding  to  disease  incidence,  as  influenced  through 
contact  transmission  in  the  case  of  measles.     Under  these  cir- 


FiG.  1. — Mexican  corral,  city  of  San  Antonio.  Front  view.  The  death  rate 
from  tuberculosis  among  residents  of  buildings  of  this  character  is  609  per 
100,000,  over  four  times  that  of  the  registration  area.  Lack  of  facilities  for  the 
promotion  of  personal  hygiene,  as  well  as  gross  overcrowding,  in  dwelling  of  this 
character,  favor  contact  transmission.  (From  Public  Health  Reports,  April  23, 
1915,  U.  S.  P.  H.  S.) 

cumstances  it  will  frequently  be  possible  to  observe  a  primary 
and  secondary  relationship  between  the  cases  that  arise,  the 
primary  case  of  course  serving  as  the  local  source  of  infection. 
(c)  It  is  to  be  noted  that  most  of  the  so-called  "children's 
diseases  are  included  in  the  group,  "commonly  transmitted  by 
contact."  In  other  words,  these  diseases  are  most  commonly 
observed  during  the  period  of  childhood.  Several  explanations 
for  this  fact  may  be  advanced.  First,  it  may  be  due  to  the  well 
nigh  universal  susceptibility  of  children  as  compared  with  the 


38 


PRACTICAL   PREVENTIVE    MEDICINE 


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CONTACT    TRANSMISSION 


39 


active  acquired  immunity  possessed  by  most  adults.  Or,  since 
it  is  well  recognized  that  the  promiscuous  habits  of  carefree 
childhood  permit  greater  opportunities  in  the  unrestricted  trans- 
fer of  secretions,  it  is  not  improbable  that  the  greater  opportuni- 
ties for  contact  transfer  during  this  period  are  of  considerable 
importance  in  this  age  incidence. 

(d)  Contact  outbreaks  or  epidemics  are  never  explosive  in 
character,  they  are  always  relatively  slow  spreading,  with  a 
gradual  rise  and  decline.  This  is  due  to  the  multitudinous 
channels  through  which  the  infective  agents  are  disseminated, 
few  individuals  being  simultaneously  infected  from  one  source 
as  contrasted  with  the  explosive  character  of  outbreaks  follow- 


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Oysters 

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Fig.  3. — Illustrating  the  participation  of  several  routes  of  dissemination  in   the 
propagation  of  the  typhoid  bacillus.      (From  U.  S.  P.  H.  S.) 

ing  the  distribution  of  infected  water  or  food,  where  a  single 
contaminated  vehicle  has  simultaneously  infected  a  considerable 
number  of  persons. 

(e)  Seasonally,  contact  diseases  tend  to  reach  a  maximum 
prevalence  during  the  colder  period  of  the  year.  At  this  period 
the  inclement  weather  forces  the  human  race  within  doors, 
where  the  degree  of  personal  association  is  more  intimate  than 
that  during  the  warmer  period  when  a  greater  portion  of  the 
time  can  be  spent  out  of  doors.  This  seasonal  distribution  is 
also  closely  associated  with  the  operation  of  the  public  schools. 
It  is  also  to  be  noted  that  continued  periods  of  inclement 
weather,  particularly  that  characterized  by  excessive  cloudiness 


40  PRACTICAL   PREVENTIVE    MEDICINE 

is  often  associated  with  an  increase  in  the  amount  of  contact 
transmission,  probably  by  forcing  people  within  doors,  as  well 
as  by  permitting  the  longer  survival  of  infective  agents  outside 
the  body,  due  to  the  diminished  sunlight. 

REFERENCES 

Palmer:  Opportunities  for  Contact  Infection. 

American  Journal  of  Public  Health;  IX-4,  April  1919,  p.  267 
Chapin:  Sources  and  Modes  of  Infection — Chapters  III,  IV,  V,  VI. 


CHAPTER  V 
DISEASES    TRANSMITTED    SOLELY   BY    CONTACT 

i.  From  the  standpoint  of  practical  importance,  we  have  to 
consider  here  but  two  infections,  the  so-called  venereal  diseases, 
syphilis  and  gonorrhea. 

Perhaps  in  no  other  infections  do  we  have  as  forcibly  brought 
to  our  attention  the  fact  that  the  questions  and  problems  of 
preventive  medicine  are  largely  of  a  sociologic  nature,  since 
with  these  diseases  dissemination  is  intimately  associated  with 
the  problem  of  promiscuous  sexual  intercourse  and  prostitu- 
tion. One  problem  cannot  be  solved  effectively  without  solving 
the  other  simultaneously. 

Their  essential  aspects  from  the  standpoint  of  control  and 
prevention  may  be  presented  briefly  as  follows: 

SYPHILIS 

(a)  Infective  Agent. — Treponema  pallidum. 

(b)  Source  of  Infection. — Individuals  in  the  primary  and 
secondary  stages  of  syphilis. 

(c)  Route  of  Transmission. — By  direct  personal  contact, 
usually  venereal,  with  infected  persons,  and  indirectly  by  con- 
tact with  discharges  from  the  lesions,  or  objects  freshly  con- 
taminated therewith.  Intra-uterine  infection  of  the  fetus  also 
occurs,  but  is  of  relatively  minor  importance. 

(d)  Exit  of  Infective  Agents  from  Body. — In  purulent  or  serous 
discharges  from  lesions  on  the  skin  and  mucous  membranes. 

(e)  Incubation  Period. — Usually  about  three  weeks. 

(/)  Period  of  Communicability . — As  long  as  the  lesions  are 
open  upon  the  skin  or  mucous  membranes  and  until  the  body 
is  free  from  the  infecting  organisms  as  shown  by  microscopic 
examinations  of  material  from  lesions. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — Through 
minute  abrasions  in  the  skin  or  mucous  membranes. 

(h)  Methods  of  Control. — The  Injected  Individual. — i.  Di- 
agnosis: By  clinical  symptoms  confirmed  by  the  microscopic 
examination  of  the  discharges  (dark  field)  and  by  serum  re- 
actions (Wassermann) . 

41 


42  PRACTICAL    PREVENTIVE    MEDICINE 

2.  Isolation:  Exclusion  from  sexual  contact  and  from  the 
preparation  or  serving  of  food  during  the  early  and  active  period 
of  the  disease,  otherwise  none  unless  the  patient  is  unwilling 
or  incapable  of  observing  these  precautions. 

3.  Artificial  Immunization :  None. 

4.  Quarantine:  None. 

5.  Concurrent  disinfection:  Of  all  infectious  discharges  and 
of  articles  soiled  therewith. 

6.  Terminal  Disinfection:  None. 

General  Measures.- — 1.  Education  of  the  laity  in  matters  of 
sexual  hygiene,  particularly  to  the  fact  that  continence  in  both 
sexes  and  at  all  ages  is  compatible  with  health  and  physical 
development. 

2.  Provisions  for  the  accurate  and  early  diagnosis  and  treat- 
ment of  venereal  patients,  in  hospitals  and  dispensaries,  with 
consideration  for  privacy  of  the  records,  and  further  provision 
for  following  patients  until  they  are  cured. 

3.  Repression  of  prostitution  by  the  use  of  police  power,  and 
control  of  the  use  of  living  premises. 

4.  Restriction  of  the  sale  of  alcoholic  beverages. 

5 .  Restriction  of  quack  advertisements  of  services  or  medicines 
for  the  treatment  of  sex  diseases. 

6.  Abandonment  of  the  use  of  common  towels,  cups,  toilet 
articles  and  eating  utensils. 

7.  Exclusion  of  persons  in  the  communicable  stages  of  the 
disease  from  participation  in  the  preparation  and  serving  of 
food  consumed  by  others. 

8.  Personal  prophylaxis  should  be  advised  to  those  who  ex- 
pose themselves  to  the  opportunity  for  infection. 

GONORRHEA 

(a)  Infective  Agent. — Micrococcus  gonorrhea. 

(b)  Source  of  Infective  Agent. — Acute  or  chronic  cases  or 
carriers. 

(c)  Exit  of  Infective  Agent. — In  purulent  or  serous  discharges 
from  inflamed  mucous  membranes  and  glands  of  infected  per- 
sons, viz.,  the  urethral,  vaginal  and  cervical  mucosa;  conjunc- 
tival mucous  membranes,  Bartholin's  or  Skene's  glands  in  the 
female,  and  Cowper's  and  the  prostate  glands  in  the  male. 

(d)  Routes  of  Transmission. — By  direct  personal  contact, 
usually  venereal,  with  infected  persons  and  indirectly  by  con- 
tact with  articles  freshly  soiled  with  the  discharges  of  such 
persons. 


DISEASES    TRANSMITTED    SOLELY  BY    CONTACT  43 

(e)  Incubation  Period. — One  to  eight  days,  usually  three  to 
five. 

(f)  Period  of  Communicability. — As  long  as  the  gonococcus 
persists  in  any  of  the  discharges,  whether  the  infection  be  an 
old  or  recent  one. 

(g)  Entrance  of  the  Infective  Agent  into  the  Body. — Through 
areas  of  specialized  epithelium  in  the  genitalia  or  conjunctiva. 

(A)  Methods  of  Control. — The  Infected  Individual.- — i.  Diag- 
nosis: Clinical  symptoms  confirmed  by  bacteriological 
examination. 

2.  Isolation:  When  the  lesions  are  in  the  geni to-urinary 
tract  exclusion  from  sexual  contact  should  be  enforced,  and 
when  conjunctival,  exclusion  from  school  or  contact  with 
children  as  long  as  the  discharges  contain  the  gonococcus. 

3.  Artificial  Immunization:  Active  immunization  with  stock 
or  autogenous  bacterins  is  extensively  employed  therapeuti- 
cally, but  the  results  secured  are  not  uniform.  For  obvious 
reasons  they  are  not  employed  as  a  prophylactic. 

4.  Quarantine:  None. 

5.  Concurrent  disinfection:  Of  discharges  from  lesions  and 
articles  soiled  therewith. 

6.  Terminal  Disinfection:  None. 

General  Measures. — i.  Same  as  those  enumerated  under  this 
heading  with  syphilis. 

2.  Use  of  prophylactic  silver  solution  in  the  eyes  of  the  new 
born.     (See  preventable  blindness.) 

PREVALENCE  OF  VENEREAL  DISEASES 

Existing  morbidity  and  mortality  statistics  do  not  give  us 
an  accurate  idea  of  the  prevalence  of  these  diseases  in  the 
United  States,  neither  can  some  of  the  estimates  published  by 
certain  ardent  champions  of  sex  hygiene  be  considered  as 
reliable.  The  army  experience  gives  probably  as  accurate  an 
idea  as  any.  Thus  according  to  Vedder,  of  the  new  recruits 
received  prior  to  the  recent  war,  7.75  per  cent,  were  undoubtedly 
syphilitic;  and  9  per  cent,  more,  probably  had  syphilis.  In  the 
second  million  of  the  army  raised  by  draft  for  the  recent  war, 
the  incidence  of  venereal  diseases,  at  the  time  when  received, 
was  5.4  per  1000  men.  (See  Fig.  3  a.)  Among  the  sailors 
treated  by  the  Marine  Hospital  Service  it  is  found  that  8.15 
per  cent,  of  the  annual  cases  are  venereal.  As  a  result  of  studies 
upon  this  question,  Banks  estimates  that  3  per  cent,  of  males 


44 


PRACTICAL    PREVENTIVE    MEDICINE 


acquire   venereal    infection    annually.     The   incidence   is   un- 
doubtedly higher  in  the  American  negro.     Thus  McNeil  found 


in  Galveston  that  between  25  and  30  per  cent,  of  all  negroes 
were  syphilitic.     The  higher  incidence  of  these  infections  in  the 


DISEASES    TRANSMITTED    SOLELY   BY    CONTACT  45 

Southern  states  as  shown  in  Fig.  4,  is  due  to  the  large  propor- 
tion of  negroes  in  the  population. 

STANDARDS  FOR  THE  DISCHARGE  OF  CARRIERS 

The  Federal  Public  Health  Service  observes  the  following 
procedures    before    discharging    venereal    patients    as    non- 
infectious: 

A.  Syphilis 

The  absence  of  areas  on  the  skin  and  mucosa  from  which 
the  infective  agent  could  be  discharged. 

B.  Gonorrhea 

1.  Males: 

(a)  Freedom  from  discharge. 

(b)  Clear  urine  without  shreds. 

(c)  Pus  expressed  from  the  urethra  by  prostatic 
massage  must  be  negative  for  gonococci  on  four 
successive  examinations  at  intervals  of  one  week. 

(d)  After  dilation  of  the  urethra  by  the  passage 
of  a  full  sized  sound,  the  resulting  inflammatory 
discbarge  must  be  negative  for  gonococci. 

2.  Females: 

(a)  No  urethral  or  vaginal  discharge. 

(b)  Two  successive  negative  examinations  for  gon- 
ococci of  the  secretions  of  the  urethra,  vagina,  and 
cervix,  with  an  interval  of  48  hours  between,  and 
repeated  on  four  successive  weeks. 

MEDICAL  PROPHYLAXIS  OF  VENEREAL  DISEASES 

The  prompt  application  of  disinfecting  substances  to  the 
genitalia  shortly  after  intercourse  with  prostitutes  has  given 
excellent  results  in  the  army  and  navy.  This  method  has 
justly  received  criticism,  inasmuch  as  it  does  not  tend  to  en- 
courage continence.  The  following  has  been  employed  for  this 
purpose: 

(a)  Scrub  the  entire  penis  with  green  soap  and  water. 

(b)  Wash  the  penis  well  with  1:2000  bichloride  of  mercury, 
paying  especial  attention  to  the  frenum. 

(c)  Have  the  patient  pass  his  urine  and  give  an  urethral 
injection  of  2  per  cent,  protargol,  which  is  retained  for  1  to  2 
minutes. 

The  following  results  with  this  treatment  were  secured  in  the 
U.  S.  Navy  between  May  1,  19 10  and  Aug.  31,  191 1. 


46  PRACTICAL    PREVENTIVE    1LEDICINE 

When  applied  within  8  hours  after  exposure,  there  were  19 
infections  in  1385  cases,  or  1.37  per  cent. 

When  applied  within  8  to  12  hours  after  exposure  there  were 
25  infections  in  741  cases,  or  3.31  per  cent. 

When  applied  within  12  to  24  hours  after  exposure  there  were 
a6  infections  in  920  cases,  or  5.00  per  cent. 

PREVENTABLE  BLINDNESS 

This  question  can  perhaps  be  best  considered  at  this  time, 
in  as  much  as  certain  aspects  are  closely  associated  with  the 
venereal  diseases. 

There  are  approximately  64,000  registered  blind  in  the  United 
States  of  whom  10  per  cent,  owe  their  blindness  to  ophthalmia 
neonatorum,  while  59  per  cent,  of  the  admissions  to  special 
schools  for  the  blind  owe  their  handicap  to  the  same  infection. 
Other  causes  of  blindness  are  the  ophthalmias  of  later  life,  syphilis, 
sympathic  inflammations,  industrial  and  other  accidents,  pro- 
gressive near  sightedness,  functional  disturbances  of  vision, 
amaurosis  and  optic  atrophy  caused  by  poisoning  from  lead, 
alcohol,  tobacco,  etc.,  and  wood  alcohol. 

(a)  Ophthalmia  neonatorum. — This  term  includes  all  in- 
flammatory conditions  of  the  conjunctiva  that  occur  before  the 
end  of  the  first  month  of  life.  Infection  usually  occurs  during 
the  passage  of  the  child  through  the  parturient  canal  and  is 
derived  from  the  vaginal  secretions  of  the  mother,  though  it 
may  also  occur  from  infection  after  birth.  The  gonococcus  is 
the  most  important  single  organism  in  its  production,  being 
demonstrated  in  about  65  per  cent,  of  the  cases.  This  disease 
is  observed  in  from  6  to  10  of  each  1000  births. 

It  may  be  effectually  prevented  by  the  employment  of  Crede's 
method  of  prophylaxis,  which  should  be  always  used  regardless  of 
the  venereal  history  of  the  parents.  It  is  as  follows:  Clean  the 
eyes  with  a  pledget  of  cotton  and  boric  acid  solution.  Sepa- 
rate the  lids  and  instill  1  to  2  drops  of  1  per  cent,  silver  nitrate 
solution,  which  in  a  few  minutes  is  washed  out  with  saline. 
In  order  to  encourage  this  practice  many  states  distribute  free 
outfits  of  these  solutions  for  the  employment  of  this  treatment 
in  all  newly  born. 

(b)  Trachoma  is  probably  not  a  specific  infection,  although 
this  is  disputed.  It  is  found  among  those  living  under 
defective  sanitary  conditions,  and  is  extremely  chronic.  Infec- 
tion is  transmitted  by  the  conjunctival  secretions  which  are 
disseminated  by  the  fingers,  roller  towels  and  handkerchiefs. 


DISEASES    TRANSMITTED    SOLELY   BY    CONTACT  47 

REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene,  3rd  Ed.,  pp.  54-74. 

Vedder:  Prevalence  of   Syphilis  in  the  Army.     Bulletin  8,   Office  of  Surgeon 

General,  U.  S.  Army. 
Pusey:  Syphilis    as    a    Modern    Problem.     American    Medical    Association. 
Clark   axd  Schereshewsky:  Trachoma:  its  Character  and  Effects,  U.S.P.H 

and  M.  H.  Service. 
A   Symposium  on  Venereal   Disease   Control  in  the  Army,  the  Navy  and  the 

Civilian    Community.     By    Gorgas,    Russell,    Holcomb,  Fosdick,  Kerr,  and 

Frost.  Social  Hygiene:  IV— i,  Jan.,  1918. 
A    Manual    for     the    Treatment    of    Venereal   Diseases.     American    Medical 

Association,  Chicago. 
The  control  of  venereal  disease.     Reprint  447,  Public  Health  Reports. 
Syphilis,    some    of    its    public    health    aspects.     Reprint   354,   Public   Health 

Reports. 
A    state    plan    for  the  prevention    of    venereal  disease.     Reprint  455,  Public 

Health  Reports. 
Instructions  to  medical  officers  in   charge  of  state  control  of  venereal  disease 

Misc.  Pub.  19.  U.  S.  P.  H.  S. 
Trachoma  in  Kentucky.     Reprint  101,  Public  Health  Reports. 


CHAPTER  VI 
DISEASES  USUALLY  TRANSMITTED  BY  CONTACT 

This  group  includes  the  diseases  whose  infective  agents  are 
most  commonly  propagated  by  secretions  leaving  by  the  mouth 
and  nose,  and  for  number  exceed  in  importance  the  other 
groups.  Thus  we  have  to  consider  by  reason  of  this  importance, 
the  following: 

Chicken  Pox  Diphtheria 

German  Measles  Influenza 

Measles  Leprosy 

Mumps  Pneumonia  (acute  lobar) 

Poliomyelitis  Scarlet  Fever 

Septic  Sore  Throat  Small  Pox 

Tuberculosis  (pulmonary)  Whooping  Cough. 

Cerebrospinal  Meningitis 

SMALL-POX 

(a)  Infective  Agent. — Unknown,  but  it  is  a  filterable  virus. 

(b)  Source  of  Infection. — Typical  or  atypical  cases  in  the 
active  or  prodromal  stages. 

(c)  Exit  of  Infective  A  gent. — In  the  secretion  s  of  the  mouth  an  d 
nose  (possibly  the  feces  and  urine)  and  discharges  from  the 
lesions. 

(d)  Routes  of  Transmission. — By  direct  or  indirect  personal 
contact,  and  possibly  by  flies. 

(e)  Incubation  Period. — Ordinarily  12  to  14  days,  sometimes 
21. 

(/)  Period  of  Communicability. — From  the  first  appearance 
of  symptoms  until  the  disappearence  of  all  scabs  and  crusts. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — Probably 
through  the  nose. 

(h)  Methods  of  Control. — The  Infected  Individual. — 1.  Diag- 
nosis: By  the  clinical  manifestations.  Differentiation  of  a- 
typical  cases  from  chicken-pox  may  be  achieved  by  the  Tieche 
test. 

2.  Isolation:  Hospital  isolation  in  screened  wards  is  pref- 
erable, continued  until  the  period  of  communicability  is  over. 

48' 


DISEASES    USUALLY    TRANSMITTED   BY    CONTACT  49 

3.  Immunization  of  contacts:  By  vaccination.  There  is  no 
means  of  employing  passive  immunization. 

4.  Quarantine:  Segregation  of  all  exposed  persons  for  21 
days  from  the  date  of  last  exposure,  or  until  protected  by 
vaccination. 

5.  Concurrent  disinfection:  Of  all  discharges  and  articles 
soiled  therewith. 

6.  Terminal  disinfection:  Thorough  cleaning  and  disinfec- 
tion of  the  premises. 

General  Measures. — 1.  General  vaccination  of  all  persons 
in  infancy,  revaccination  on  entering  school,  and  of  the  entire 
population  when  the  disease  is  prevalent. 

Small-pox  Vaccination. — (a)  The  importance  of  this  means 
of  protection,  as  well  as  the  possibility  of  serious  or  untoward 
results  from  its  application,  demand  its  consideration  in  some 
detail. 

(b)  Glycerinated  virus,  put  up  for  distribution  in  capillary 
tubes  and  which  has  been  stored  in  a  refrigerator,  should  only 
be  employed.  One  should  be  sure  the  date  of  expiration  has 
not  passed,  as  it  is  exceedingly  important  to  use  fresh,  potent 
virus. 

(c)  Select  for  vaccination  the  left  arm  at  the  insertion  of  the 
deltoid.  Cleanse  the  arm  thoroughly  by  rubbing  with  green 
soap,  wash  with  water,  and  follow  with  alcohol.  Allow  the  skin 
to  dry.  With  a  flamed  needle  make  three  parallel  scratches 
about  1  to  }£  inches  long  and  %  inch  apart,  taking  care  not  to 
draw  blood.  Expel  the  contents  of  vaccine  tube  on  the  two 
outer  scratches  and  with  shaft  of  the  needle  rub  the  virus  well 
into  scratches.  Allow  to  dry  for  10  to  15  minutes.  Upon 
appearance  of  the  eruption  it  may  be  covered  with  a  sterile 
dry  dressing. 

(d)  Course  of  Eruption  in  a  Primary  Take— (a)  Period  of 
Incubation. — This  is  from  3  to  4  days  duration.  The  inocula- 
tion scratches  will  have  entirely  healed  in  two  or  three  days. 

(b)  Period  of  Papule. — Along  the  site  of  the  inoculation 
scratches  one  or  more  small,  round,  flat,  bright  red  and  super- 
ficial papules  make  their  appearance.  These  may  be 
confluent. 

(c)  Period  of  Vesicle. — On  the  fifth  day  a  small  clear  vesicle 
will  appear  in  the  center  of  each  of  the  papules.  The  area 
around  the  vesicles  becomes  red  and  swollen  and  enlarges  as 
the  vesicle  ^enlarges.  The  vesicle  is  multilocular  and  umbili- 
cated.     It  is  mature  by  the  eighth  day. 

4 


5<D  PRACTICAL   PREVENTIVE    MEDICINE 

(d)  Period  of  the  Pustule. — By  the  ninth  day  the  center  of 
the  vesicle  becomes  pustular,  the  skin  is  swollen,  hot,  and  fever- 
ish, and  the  axillary  glands  are  enlarged.  The  areola  com- 
mences to  fade  by  the  ninth  day. 

(e)  Period  of  Scabbing. — By  the  nth  to  12th  day  the  pustules 
begin  to  dessicate  and  form  a  scab,  which  falls  off  after  2  to  3 
weeks,  leaving  a  red  scar,  which  later  turns  white. 

(e)  The  general  symptoms  are  most  noticeable  during  the 
stage  of  pustulation.  One  may  observe  malaise,  loss  of  appe- 
tite, nausea  and  vomiting,  headache  and  muscular  pain,  with 
1  to  2  degrees  of  fever,  which  lasts  from  3  to  7  days. 

Immunity  appears  on  the  eighth  day,  and  lasts  on  the  average 
approximately  seven  years.  The  best  time  to  vaccinate  for 
the  first  time  is  in  the  first  year  of  life  before  the  second  summer. 

(J)  Re-vaccination  may: 

(a)  Run  a  course  resembling  the  primary  take.  In  this 
event  the  cow-pox  immunity  has  disappeared,  or, 

(b)  Run  a  slightly  more  rapid  course  (Accelerated  Reaction) . 
The  incubation  period  is  short  and  pustulation  occurs  by  the 
sixth  day,  or, 

(c)  With  an  incubation  period  of  24  hours  or  less,  an  imme- 
diate reaction,  which  presents  a  small  papule  or  erythema  that 
later  fades,  may  occur  in  immune  persons. 

(g)  Vaccination  of  Exposed  Persons. — (a)  If  done  during  or 
immediately  before  the  primary  fever  of  small-pox  it  does  not 
influence  the  disease  nor  does  it  take. 

(b)  If  done  in  the  last  stages  of  the  small-pox  incubation 
period  it  takes,  but  the  two  infections  run  a  simultaneous  course 
without  influencing  each  other. 

(c)  If  done  during  the  6th  to  8th  day  of  incubation,  so  that  its 
eruption  is  mature  before  the  onset  of  small-pox,  it  will  prevent 
or  abort  the  disease. 

Individuals  in  whom  the  vaccination  immunity  is  waning 
may  contract  small-pox,  but  the  disease  will  run  a  very  mild 
course  (varioloid). 

CHICKEN-POX 

This  disease  is  of  very  little  importance  itself  but  great 
difficulties  arise  from  the  fact  that  mild  discrete  small-pox  may 
be  mistaken  for  it. 

(a)  Infective  Agent. — Is  unknown  but  is  thought  to  be  a 
filter    passer. 


DISEASES    USUALLY    TRANSMITTED   BY    CONTACT  5 1 

(b)  Source  of  Infection. — Typical  cases  or  atypical  cases  in 
the  active  or  prodromal  period. 

(c)  Exit  of  Infective  Agent.- — In  the  discharges  from  lesions  on 
the  skin  and  mucosa,  and  as  a  consequence  of  the  latter  the 
buccal  and  nasopharyngeal  secretions  are  probably  infective. 

(d)  Route  of  Transmission. — By  direct  or  indirect  contact. 

(e)  Incubation   Period. — Two  to  three  weeks. 

(/)  Period  of  Communicability .- — Until  the  primary  scabs 
have  disappeared  from  the  mucous  membranes  and  the  skin. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — Probably 
by  the  mouth  and  nose. 

(h)  Methods  of  Control. — The  Infected  Individual. — i.  Diag- 
nosis: Based  upon  clinical  manifestations.  The  Tieche  sen- 
sitization test  for  differentiation  from  small  pox  is  very  valuable. 
The  differentiation  of  chicken-pox  from  small-pox  is  of  especial 
importance  in  those  over  15  years  of  age. 

2.  Isolation:  Exclusion  of  the  patient  from  school  and 
prevention  of  his  contact  with  susceptibles. 

3.  Artificial  immunization:  Not  available. 

4.  Quarantine:  Not  required. 

5.  Concurrent  disinfection:  Of  articles  soiled  by  discharges 
from  the  lesions  and  the  bucco-nasal  secretions. 

6.  Terminal  disinfection:  Thorough  cleaning. 
General  measures  of  control  are  not  required. 

MEASLES 

(a)  Infective  Agent. — Is  unknown,  but  is  known  to  be  a 
filterable  virus. 

(b)  Source  of  Infection.- — Cases  in  the  active  and  prodromal 
stages. 

(c)  Exit  of  Infective  Agent. — In  the  buccal  and  nasal  secre- 
tions. 

(d)  Route  of  Transmission. — By  direct  or  indirect  contact. 

(e)  Incubation  Period. — Seven  to  eighteen  days;  practically 
always  fourteen  days. 

(f)  Period  of  Communicability.- — During  the  period  of  catarr- 
hal symptoms  and  until  the  cessation  of  abnormal  mucous 
membrane  secretions;  which  is  from  2  days  before,  to  5  days 
after  the  appearance  of  the  rash;  a  minimum  period  of  seven 
days. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — Probably  by 
the  mouth  and  nose. 


52  PRACTICAL   PREVENTIVE    MEDICINE 

(h)  Methods  of  Control. — The  Infected  Individual. —  i.  Di- 
agnosis: By  the  clinical  manifestations.  In  exposed  individuals 
pay  especial  attention  to  the  rise  in  temperature,  Koplik  spots 
on  the  buccal  mucosa  and  catarrhal  symptoms. 

2.  Isolation:  During  the  period  of  communicability. 

3.  Artificial  immunization:  None. 

4.  Quarantine:  Exclude  exposed  susceptible  school  children 
and  teachers  from  school  for  a  period  of  one  week  dating  from 
the  last  known  exposure.  This  also  applies  to  all  public 
gatherings. 

5.  Concurrent  disinfection:  Of  all  articles  soiled  with  the 
secretions  of  the  nose  and  throat. 

6.  Terminal  disinfection:  Thorough  cleaning. 

General  Measures. — 1.  Daily  examination  of  exposed  children 
during  the  incubation  period,  and  of  other  persons  presumably 
exposed.  This  examination  should  include  a  record  of  the  body 
temperature.  A  non-immune  exposed  individual  exhibiting  a 
rise  of  temperature  of  0.5  degree  or  more  should  be  promptly 
isolated  pending  diagnosis. 

2.  Schools  should  not  be  closed  or  classes  discontinued  where 
daily  observation  of  the  children  by  a  physician  or  nurse  is 
possible. 

3.  Education  of  parents  and  others  of  the  great  danger  from 
exposing  young  children  to  those  exhibiting  acute  catarrhal 
symptoms  of  any  kind. 

MUMPS 

(a)  Infective  Agent. — Unknown. 

(b)  Source  of  Infection. — Typical  cases  and  atypical  recurring 
cases. 

(c)  Exit  of  Infective  Agent. — In  the  buccal  and  nasal  secretions, 

(d)  Route  of  Transmission. — Direct  and  indirect  contact. 

(e)  Incubation  Period. — From  4  to  25  days,  usually  18  days. 

(f)  Period  of  Communicability. — Unknown,  but  it  is  assumed 
to  continue  until  the  parotid  gland  has  returned  to  normal  size. 

(g)  Entrance  of  Infective  Agent  into  the  'Body. — Probably  by 
the  mouth. 

(/z)  Methods  of  Control. — The  Infected  Individual. — 1.  Di- 
agnosis: Inflammation  of  Steno's  duct  may  be  of  assistance  in 
recognizing  the  early  stage  of  the  disease.  The  diagnosis  is 
usually  made  from  the  swelling  of  the  parotid  gland. 

2.  Isolation:   Separation   of   the  patient  from  non-immune 


DISEASES    USUALLY    TRANSMITTED   BY    CONTACT  53 

children  and  exclusion  of  the  patient  from  school  and  public 
places  for  the  period  of  the  presumed  infectivity. 

3.  Artificial  Immunization:  None. 

4.  Quarantine:  Limited  to  exclusion  of  non  immune  children 
from  school  and  public  gatherings  for  21  days  after  their  last 
exposure  to  a  recognized  case. 

5.  Concurrent  disinfection:  Of  all  articles  soiled  with  the  dis- 
charges from  the  nose  and  mouth. 

6.  Terminal  disinfection:  None. 
General  Measures. — Not  required. 

REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene,  3rd  Ed.,  pp.,  1-36,172-176;  187-309. 
Camac  :  Epoch  making  Contributions  to  Medicine,  Surgery  and  the  Allied  sciences, 

Containing  a  reprint  of  Jenner's  '"Inquiry." 
Final  report  of  the  Royal  Commission  on  Vaccination. 
Measles:  Supplement  1,  Public  Health  Reports. 
Post  vaccination  tetanus,  Reprint  289,  Public  Health  Reports. 
Plan  of  organization  for  suppression  of  small-pox  in  communities  not  provided 

with  organized  Boards  of  Health.     Reprint  2,  Public  Health  Reports. 
Force:  Etiology  and  Laboratory  Diagnosis  of   Small  pox  and  Chicken  pox 

(Tieche  test).    Jour.  Lab.  and  Clin.  Med.  I  p.  243. 


CHAPTER   VII 

DISEASES  USUALLY  TRANSMITTED  BY  CONTACT 

(Continued) 

GERMAN  MEASLES 

The  public  health  importance  of  this  disease  is  similar  to  that 
of  chicken-pox,  confusion  with  scarlet  fever  being  not  infre- 
quent. 

(a)  Infective  Agent. — Unknown. 

(b)  Source  of  Infection. — Typical  cases  and  atypical  missed 
cases  of  the  disease. 

(c)  Exit  of  Infective  Agent. — In  the  buccal  and  nasal  secre- 
tions. 

(d)  Route  of  Transmission. — By  direct  and  indirect  contact. 

(e)  Incubation  Period. — From  10  to  21  days. 

(/)  Period  of  Communicability .■ — For  eight  days  from  the  onset 
of  the  disease. 

(g)  Entrance  of  Infective  Agent  into  Body. — Probably  by  the 
the  mouth. 

(h)  Methods  of  Control. — Infected  Individual. — 1.  Diagnosis: 
Only  by  clinical  manifestations. 

2.  Isolation:  Separation  of  the  patient  from  susceptible  chil- 
dren, and  exclusion  from  school  and  public  places  for  the  period 
of  the  presumed  infectivity. 

3.  Artificial  immunization:  None. 

4.  Quarantine:  None,  except  exclusion  of  non-immune  chil- 
dren from  school  and  public  gatherings  from  1 1  to  2  2  days  from 
the  date  of  exposure  to  a  recognized  case. 

5.  Concurrent  disinfection:  Of  the  discharges  from  the  nose 
and  throat  and  of  all  articles  soiled  with  them. 

6.  Terminal  disinfection:  Airing  and  cleaning. 
General  Measures  are  not  required. 

SCARLET  FEVER 

(a)  Infective  Agent. — Is  unknown;  but  by  some  is  considered 
to  be  a  streptococcus. 

54 


DISEASES    USUALLY    TRANSMITTED   BY    CONTACT  55 

(b)  Source  of  Infection. — Typical  cases,  atypical  cases  and 
carriers.  ^ 

(c)  Exit  of  Infective  Agent. — In  the  secretions  of  the  mouth 
and  nose  and  in  purulent  discharges  from  suppurating  ears  and 
lymph  nodes. 

(d)  Route  of  Transmission. — By  direct  or  indirect  contact; 
or  by  milk  contaminated  with  buccal-pharyngeal  secretions. 

(e)  Incubation  Period.- — From  2  to  7  days,  usually  3  to  4  days. 
(/')  Period  of  Communicability  .■ — Up  until  four  weeks  from 

the  onset  of  the  illness  without  regard  to  desquamation,  and 
until  all  abnormal  discharges  have  stopped  and  the  open  lesions 
have  healed. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — Probably  by 
mouth  or  nose. 

(ti)  Methods  of  Control. — Infected  Individual. — 1.  Diagnosis: 
By  clinical  manifestations. 

2.  Isolation:  At  home  or  in  a  hospital,  maintained  until  the 
termination  of  infectivity. 

3.  Artificial  Immunization:  None. 

4.  Quarantine:  Exclusion  of  exposed  susceptible  children  and 
teachers  from  school,  and  of  food  handlers  from  their  work, 
until  seven  days  have  elapsed  since  the  last  known  exposure. 

5.  Concurrent  disinfection:  Of  all  discharges  of  the  patient 
and  of  all  objects  contaminated  with  them. 

6.  Terminal  disinfection:  Thorough  cleaning. 

General  Measures. — 1.  Daily  examination  of  exposed  children 
and  other  susceptible  contacts  for  a  week  after  their  last 
exposure. 

2.  Schools  should  not  be  closed  where  daily  observation  of 
the  children  by  a  physician  or  nurse  is  provided. 

3.  Education  of  parents  and  others  in  the  danger  of  exposing 
children  to  those  persons  who  exhibit  acute  catarrhal  symptoms 
of  any  kind. 

4.  Pasteurization  of  all  public  milk  supplies  should  be  re- 
quired. 

SEPTIC  SORE  THROAT 

(a)  Infective  Agent. — Streptococcus  hemolyticus. 

(b)  Source  of  Infection. — Typical  or  atypical  human  cases  or 
carriers.  Cows  may  be  healthy  carriers,  becoming  infected 
from  man. 

(c)  Exit  of  Infective  Agent. — In  the  nasopharyngeal  secretions 
of  human  beings,  or  in  the  milk  of  a  carrier  cow. 


56  PRACTICAL   PREVENTIVE    MEDICINE 

(d)  Route  of  Transmission. — Direct  or  indirect  human  con- 
tact; consumption  of  infected  cow's  milk,  or  by  contaminated 
cow's  milk. 

(e)  Incubation  Period. — From  one  to  three  days. 

(f)  Period  of  Communicability.- — Indefinite  and  uncertain  and 
can  only  be  ascertained  by  a  bacteriological  examination. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — Through  the 
mouth  or  nose. 

(h)  Methods  of  Control. — Infected  Individual. — 1 .  Diagnosis : 
By  clinical  manifestations  which  should  be  confirmed  by  cul- 
tures from  the  throat  and  tonsils. 

2.  Isolation:  During  the  clinical  course  of  the  disease  and 
convalescence,  especially  by  exclusion  of  the  patient  from  the 
production  or  handling  of  milk  or  milk  products. 

3.  Artificial  Immunization:  None. 

4.  Quarantine:  None. 

5.  Concurrent  Disinfection:  Of  discharges  from  the  nose  and 
throat  and  articles  soiled  therewith. 

6.  Terminal  Disinfection:  None. 

General  Measures. — 1.  Exclusion  of  a  suspected  milk  supply 
from  public  sale  or  use  until  it  has  been  pasteurized.  The  ex- 
clusion of  the  milk  of  an  infected  cow  is  possible  in  small  herds 
if  the  infected  animal  is  located  by  the  bacteriological  exami- 
nation of  all  in  the  herd. 

2.  Pasteurization  of  all  milk  retailed  to  the  public. 

3.  Education  of  the  public  in  the  principles  of  personal  hy- 
giene, especially  in  the  avoidance  of  the  use  of  common  towels, 
and  common  drinking  and  eating  utensils. 

WHOOPING-COUGH 

(a)  Infective  Agent. — Bacterium  pertussis. 

(b)  Source  of  Infection. — Typical  cases,  atypical  cases  and 
carriers,  and  also  dogs  and  cats. 

(c)  Exit  of  Infective  Agent. — In  the  discharges  from  the  laryn- 
geal and  bronchial  mucous  membranes. 

(d)  Route  of  Transmission. — By  direct  or  indirect  contact. 

(e)  Incubation  Period. — Not  over  14  days. 

(/)  Period  of  Communicability. — It  is  particularly  communi- 
cable in  the  early  catarrhal  stages  before  the  onset  of  the 
whooping.  It  probably  does  not  persist  longer  than  two  weeks 
after  the  onset  of  the  characteristic  cough. 

(g)  Entrance  of  Infective  Agent  into  the  Body.- — Through  the 
mouth  and  nose. 


DISEASES    USUALLY    TRANSMITTED   BY    CONTACT  57 

(//)  Methods  of  Control. — The  Infected  Individual. — i.  Di- 
agnosis: From  the  clinical  manifestations,  supported  by  a  leuco- 
cyte count  and  by  bacteriological  examination. 

2.  Isolation:  Separation  of  the  patient  from  susceptible  chil- 
dren and  his  exclusion  from  school  and  public  places  for  the 
period  of  presumed  infectivity. 

3.  Artificial  Immunization:  Some  observers  recommend  the 
employment  of  B.  pertussis  vaccine,  although  the  results  do 
not  seem  to  be  uniformly  effective. 

4.  Quarantine:  Exclusion  of  non-immune  children  from  school 
and  public  places  for  14  days  after  their  last  exposure  to  a  known 
case. 

5.  Concurrent  Disinfection:  Of  the  secretions  of  the  mouth, 
nose  and  throat  of  patients,  and  of  articles  soiled  therewith. 

6.  Terminal  Disinfection:  Cleaning. 

General  Measures. — Education  of  the  public  in  habits  of  clean- 
iness  and  in  the  danger  of  association  or  contact  with  those 
showing  catarrhal  symptoms  or  with  a  cough. 

INFLUENZA 

(a)  Infective  Agent. — Unknown  and  disputed.  Evidence  for 
and  against  the  Bacterium  influenza  is  conflicting. 

(b)  Source  of  Infection. — Typical  or  atypical  human  cases. 

(c)  Exit  of  Infective  Agent. — In  the  nasopharyngeal  secre- 
tions. 

(d)  Routes  of  Transmission. — Direct  or  indirect  human  con- 
tact. 

(e)  Incubation  Period. — One  to  three  days. 

(/)  Period  of  Communicability. — Indefinite  and  uncertain. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — Through  the 
mouth  or  nose. 

(h)  Methods  of  Control. —  The  Infected  Individual. — 1.  Di- 
agnosis: From  clinical  manifestations. 

2.  Isolation:  Separation  of  patients  from  susceptibles  for  the 
period  of  their  illness. 

3.  Artificial  Immunization:  In  the  abscence  of  definite 
knowledge  of  the  causative  organism,  there  is  no  scientific 
basis  for  the  employment  of  vaccines  as  a  prophylactic  measure, 
a  fact  which  is  substantiated  by  the  universal  failure  of  the  vari- 
ous bacterins  employed  for  this  purpose  in  1919.  No  methods 
of  artificial  active  or  passive  immunization  are  at  present 
known. 


58  PRACTICAL   PREVENTIVE    MEDICINE 

4.  Quarantine:  None. 

5.  Concurrent  Disinfection:  Of  the  secretions  of  the  mouth 
and  nose,  and  of  articles  contaminated  therewith. 

6.  Terminal  Disinfection:  Cleaning. 

General  Measures.— Education  of  the  public  in  habits  of 
personal  cleanliness  and  in  the  danger  of  association  or  contact 
with  those  showing  catarrhal  symptoms  or  with  cough.  The 
masking  of  all  persons  during  epidemics  is  of  value. 

REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene,  3rd.  pp.  192;  184;  178. 
Whooping-cough:  Its  Nature  and  Prevention.  Reprint  100. 

Public  Health  Reports. 
Septic  Sore  Throat:  Reprint  103,  Public  Health  Reports. 


CHAPTER     VIII 

DISEASES  USUALLY  TRANSMITTED  BY  CONTACT 

(Continued) 

DIPHTHERIA 

(a)  Infective  Agent. — Mycobacterium  diphtherice. 

(b)  Source  of  Infection. — Typical  or  atypical  cases  or  carriers. 

(c)  Exit  of  Infective  Agent. — Most  commonly  in  the  secretions 
of  the  mouth  and  nose,  which  are  contaminated  from  lesions 
situated  in  the  nose  and  throat.  Less  frequent  and  of  lesser 
importance  are  lesions  on  the  conjunctiva,  infection  of  wounds 
and  of  the  vagina. 

{d)  Routes  of  Transmission. — By  direct  or  indirect  contact, 
and  by  milk  or  milk  products  contaminated  with  bucco-nasal 
secretions  from  cases  or  carriers. 

(e)  Incubation  Period. — Usually  2  to  5  days,  sometimes  longer 
in  the  case  of  incubatory  carriers. 

(/)  Period  of  Communic ability. — Until  virulent  bacilli  have 
disappeared  from  the  secretions  and  lesions  as  determined  bac- 
teriologically.  Their  persistance  is  variable,  in  75  per  cent,  of 
the  cases  they  disappear  within  two  weeks,  in  95  per  cent,  within 
4  weeks.  In  exceptional  carriers  they  may  persist  for  2  to  6 
months. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — The  organism 
does  not  penetrate  the  physiological  interior  of  the  body.  Most 
commonly  it  gains  access  to  the  mouth  or  nose. 

(h)  Methods  of  Control. — The  Infected  Individual. — 1.  Diag- 
nosis: Clinical  manifestations  together  with  bacteriological 
examination,  or  the  latter  alone. 

2.  Isolation:  Until  two  consecutive  negative  cultures  are 
secured  from  both  the  nose  and  the  throat,  taken  not  less  than 
twenty-four  apart  and  not  less  than  4  hours  subsequent  to  the 
local  employment  of  antiseptics.  Some  authorities  advocate 
the  termination  of  isolation  with  diphtheria  bacilli  present 
providing  the  latter  give  negative  virulence  tests. 

3.  Artificial  Immunization:  Susceptible  contacts  who  are 
found   to  be  carriers  should  be  given  prophylactic  doses   of 

59 


6o 


PRACTICAL   PREVENTIVE    MEDICINE 


antitoxin.  Contacts  in  whom  the  diphtheria  bacillus  is  not 
found  and  who  give  a  positive  Schick  reaction,  indicating  their 
susceptibility  to  diphtheria  toxin,  should  be  actively  immunized 
by  toxin-antitoxin  mixtures,  the  administration  of  which  is 
controlled  by  the  Schick  test. 

The  Schick  test  consists  in  the  intracutaneous  injection  of 
li^th.  of  the  M.  L.  D.  of  a  diphtheria  toxin  contained  in  .1 
to  .2  c.  c  of  saline.  A  negative  reaction  is  a  sign  of  immunity, 
and  a  positive  reaction  a  sign  of  susceptibility.  Less  than 
%oth  of  an  antitoxin  unit  per  c.c.  of  blood  makes  an  individual 
susceptible.     A   positive   reaction  runs  the  following   course: 

In  from  12  to  24  hours  there  is  a  trace  of  redness 
24  to  48  hours  there  is  a  distinct  reaction 
3    to  4    days   the  reaction  is  at  a  maximum   and 
waning. 

3    to  6    weeks  there  is  a  circumscribed  area  of  scaling 

and  for  pigmentation.  Pseudo  reactions  have  a  more  rapid 
course  and  leave  no  pigmentation. 

Active  immunization  against  diphtheria  toxin  is  accomplished 
by  injecting  overneutralized  mixtures  of  toxin  and  antitoxin. 
These  mixtures  should  contain  per  c.c.  from  eighty  to  ninety 
per  cent,  of  the  limes  plus  dose  of  toxin  and  one  antitoxin  unit. 
One  c.c.  is  a  dose  and  it  should  be  given  subcutaneously  and 
repeated  at  intervals  of  six  to  eight  days.  This  method  of 
immunization  is  employed  upon  susceptibles  to  the  toxin  as  re- 
vealed by  the  Schick  test. 

The  employment  of  diphtheria  antitoxin  as  a  therapeutic  agent 
effected  a  gross  reduction  in  the  mortality  from  diphtheria  of 
85  per  cent.  The  present  mortality  from  diphtheria  is  largely 
due  to  either  its  delayed  administration  or  its  employment  in 
insufficient  amounts.  The  following  doses  are  recommended  by 
Park  and  Biggs  as  minimal : 

Minimal  Dosages  of  Diphtheria  Antitoxin 


Patient 


Mild 


Moderate 


Units  in  cases 


Severe  Very  severe 


Under  1  yr 

1-5  yrs 

5-9  yrs 

10  yrs.  and  over 


2,000 
3,000 
4,000 
5,000 


3,000 

5,000 

5,000 

10,000 


10,000 
10,000 
10,000 
10,000 


10,000 
10,000 
15,000 
20,000 


DISEASES   USUALLY   TRANSMITTED  BY   CONTACT  6 1 

In  any  event  its  administration  should  be  continued  until  the 
desired  result  is  secured.  It  is  better  to  give  the  above  indi- 
cated amounts  as  one  single  dose  and  add  additional  quantities 
as  the  course  of  the  case  may  require.  The  quickest  results 
and  the  maximum  benefit  is  secured  from  the  intravenous  route 
of  injection.  In  order  to  guard  against  anaphylactic  reactions, 
the  possibility  of  the  patient's  sensitization  to  horse  serum 
must  always  be  borne  in  mind,  and  de-sensitization  performed 
if  necessary. 

4.  Quarantine:  Of  all  exposed  persons  until  shown  to  be 
free  from  infection  by  bacteriological  examination. 

5.  Concurrent  Disinfection:  Of  all  secretions  of  the  infected 
person  and  articles  which  have  been  contaminated  therewith. 

6.  Terminal  Disinfection:  Thorough  airing  and  scrubbing 
of  the  isolation  quarters. 

General  Measures.  —  i.  Pasteurization  of  the  public  milk 
supply. 

2.  Application  of  the  Schick  test  to  all  children. 

3.  Application  of  the  Schick  test  to  all  contacts  and  the  active 
immunization  of  all  found  to  be  susceptible. 

4.  Active  immunization  by  toxin-antitoxin  mixtures  of  all 
susceptibles. 

5.  Determination  of  the  presence  or  absence  of  carriers  among 
the  population  at  large. 

MENINGOCOCCI  MENINGITIS  (CEREBRO -SPINAL) 

(a)  Infective  Agent. — Micrococcus  meningitidis. 

(b)  Source  of  Infection. — Typical  or  atypical  cases  and 
carriers. 

(c)  Exit  of  Infective  Agent.— In  the  secretions  of  the  mouth 
and  nose. 

(d)  Routes  of  Transmission. — By  direct  and  indirect  contact. 

(e)  Incubation  Period. — Commonly  7  days,  varying  from 
2  to  10.  In  the  case  of  incubatory  carriers  it  may  be  of  longer 
duration. 

(J)  Period  of  Communicability. — Until  the  meningococcus  is 
no  longer  present  in  the  secretions  of  the  nose  and  throat  as 
determined  bacteriologically. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — Probably  by 
the  mouth  and  nose.  Meningitis  is  probably  a  rather  infre- 
quent complication  in  an  infection  commonly  localized  to  the 
naso-pharynx. 


62  PRACTICAL   PREVENTIVE    MEDICINE 

(k)  Methods  of  Control.  Infected  Individuals. — i.  Diag- 
nosis: Clinical  manifestations  confirmed  by  bacteriological  ex- 
amination of  the  spinal  fluid,  or  of  the  nasal  and  pharyngeal 
secretions. 

2.  Isolation:  Until  the  naso-pharynx  is  free  from  the  infecting 
organisms;  or  in  the  absence  of  bacteriological  assistance,  until 
one  week  after  the  fever  has  subsided. 

3.  Artificial  Immunization:  The  employment  of  vaccines 
may  prove  of  value,  though  still  in  the  experimental  stage. 

The  therapeutic  employment  of  anti-meningococcus  serum 
has  effected  a  reduction  of  the  mortality  from  this  disease  of 
from  thirty  to  eight  per  cent  as  compared  with  the  mortality 
in  those  not  treated  with  the  serum.  The  serum  is  given  in- 
traspinously  after  removal  of  an  equal  volume  of  spinal  fluid. 
The  recognition  of  at  least  four  distinct  types  of  meningococci, 
and  the  additional  fact  that  antiserum  produced  against  any 
one  type  alone  is  of  but  slight  value  in  treating  cases  due  to 
the  other  types,  indicates  the  importance  of  employing  either 
a  polyvalent  serum,  or  where  facilities  for  determining  the  type 
of  the  infecting  meningococcus  are  available  the  employment 
of  the  specific  antisera  against  the  infecting  type  strain.  No 
quantity  of  serum  can  be  regarded  as  a  minimal  dose.  Its 
administration  should  be  pushed  until  the  desired  effects  are 
secured. 

4.  Quarantine:  None. 

5.  Concurrent  Disinfection:  Of  all  the  discharges  from  the 
mouth  and  nose  and  of  articles  soiled  therewith. 

6.  Terminal  Disinfection:  None. 

General  Measures. — 1.  Search  for  carriers  by  the  bacteriologi- 
cal examination  of  the  secretions  from  the  posterior  nares  of  all 
contacts. 

2.  Education  of  the  public  in  personal  cleanliness  and  the 
avoidance  of  contact  and  droplet  infection. 

3.  Prevention  of  overcrowding  in  living  quarters,  transpor- 
tation conveyances,  working  places,  and  places  of  assemblage 
among  civil  populations,  and  in  inadequately  ventilated  closed 
quarters  and  barracks,  camps,  and  ships,  among  laboring, 
naval  and  military  units. 

POLIOMYELITIS 

(a)  Infective  Agent. — Unknown.  By  Flexner  believed  to  be 
a  filterable  virus,  by  Rosenow  a  streptococcus. 


DISEASES    USUALLY    TRANSMITTED   BY    CONTACT  63 

(b)  Source  oj  Infection. — Typical  and  atypical  cases  and 
carriers. 

(c)  Exit  of  Infective  Agent. — In  the  secretions  of  the  mouth 
and  nose  and  in  the  intestinal  discharges. 

(d)  Routes  of  Transmission. — By  direct  or  indirect  contact, 
and  also  possibly  by  flies. 

(e)  Incubation  Period. — Three  to  ten  days,  commonly  six. 

(/)  Period  of  Communicability. — Unknown.  Apparently  not 
for  more  than  21  days  from  the  date  of  onset  of  the  disease, 
but  it  may  precede  the  onset  of  the  symptoms  by  several  days. 

(g)  Entrance  oj  Infective  Agent  into  the  Body. — Probably 
through  the  mouth  or  nose. 

(/*)  Methods  of  Control.  Infected  Persons. — 1.  Diagnosis: 
From  clinical  manifestations  assisted  by  chemical  and  micro- 
scopical examination  of  the  spinal  fluid. 

2.  Isolation:  Of  all  recognized  cases  in  screened  rooms. 

3.  Artificial  Immunization:  None. 

4.  Quarantine:  Of  exposed  contacts  among  children,  and  of 
adults  whose  occupation  brings  them  in  contact  with  children, 
or  who  are  food  handlers,  for  14  days  from  the  date  of  their 
last  exposure. 

5.  Concurrent  disinfection  of  the  nose,  throat  and  bowel  dis- 
charges, or  articles  soiled  therewith. 

6.  Terminal  Disinfection:  Cleaning. 

General  Measures  During  Epidemics. — 1.  A  search  for  and 
an  examination  of  all  sick  children,  should  be  made. 

2.  All  children  with  fever  should  be  isolated  pending  di- 
agnosis. 

3.  Education  of  the  general  public  in  personal  cleanliness  and 
the  avoidance  of  contact  opportunities. 

LOBAR  PNEUMONIA,  ACUTE 

(a)  Infective  Agent. — Streptococcus  pneumonice. 

(b)  Source  of  Infection. — Typical  cases  and  carriers. 

(c)  Exit  of  Infective  Agent.  —  In  the  sputum  and  saliva. 

(d)  Routes  of  Transmission. — Direct  and  indirect  contact. 

(e)  Incubation  Period. — Short,  usually  two  to  three  days. 

(f)  Period  of  Communicability. — Of  unknown  duration,  pre- 
sumably until  the  pneumococcus  is  no  longer  present. 

(g)  Entrance  of  Infective  Agent  into  the  Body. — Through  the 
mouth  or  nose. 

Qi)  Methods  of  Control.  The  Infected  Individuals. — 1.  Di- 
agnosis :  By  the  clinical  manifestations.    The  specific  strain  of  the 


64  PRACTICAL   PREVENTIVE    MEDICINE 

pneumococcus  involved  may  be  determined  by  bacteriological 
and  serological  tests  early  in  the  disease. 

2.  Isolation:  During  the  clinical  course  of  the  disease. 

3.  Artificial  immunization:  Polyvalent  vaccines  offer  con- 
siderable promise  although  still  experimental. 

Fairly  successful  antibacterial  serum  has  been  produced 
against  one  of  the  several  known  types  of  the  pneumococcus, 
but  passive  immunizationn  has  as  yet  proven  of  little  value 
against  infection  with  the  other  types.  Hence  the  desirability 
of  early  ascertaining  the  type  of  the  infecting  strain  of  the  pneu- 
mococcus, since  if  it  is  found  to  be  type  1,  the  prognosis  can  be 
favored  by  the  therapeutic  employemnt  of  type  1  antiserum. 
The  serum  is  given  intravenously  in  large  doses,  starting  with 
75  to  100  c.c.  and  repeating  every  eight  hours.  The  average 
requirements  are  about  250  c.c. 

4.  Quarantine:  None. 

5.  Concurrent  disinfection:  Of  all  discharges  from  the  mouth 
or  nose  and  of  articles  soiled  therewith. 

6.  Terminal  disinfection:  Cleaning. 

General  Measures. — 1.  Overcrowding  should  be  carefully 
avoided  in  institutions  and  camps.  The  general  resistance  of 
healthy  persons  should  be  conserved  by  good  feeding,  fresh  air, 
and  temperance  in  the  use  of  alcoholic  beverages. 

TUBERCULOSIS     (PULMONARY) 

(a)  Infective  Agent. — Mycobacterium  tuberculosis,  most  com- 
monly the  human  strain. 

(b)  Source  of  Infection. — Typical  or  atypical  cases. 

(c)  Exit  of  Infective  Agent. — -The  most  important  portal  of 
exit  is  by  means  of  the  sputum.  The  bacilli  may  also  leave 
the  body  in  the  discharges  from  the  intestinal  and  genito- 
urinary tracts,  or  in  discharges  from  lesions  of  the  lymphatic 
glands,  bone  and  skin. 

(d)  Route  of  Transmission. — By  direct  and  indirect  contact. 

(e)  Incubation  Period. — Prolonged  and  variable,  depending 
upon  the  type  of  disease. 

(/)  Period  of  Communicability. — Commences  when  a  lesion 
becomes  open  and  continues  until  it  heals  or  death  supervenes. 
It  is  of  var'ab'.e  duration  though  usually  prolonged. 

(g)  Entrance  oj  Injective  Agent  into  Body. — By  the  mouth  or 
the  nose,  passing  either  directly  to  the  lungs  by  the  inhalation 
of  the  organisms,  or  by  way  of  the  upper  thoracic  lymphatic 


DISEASES    USUALLY   TRANSMITTED  BY   CONTACT  65 

system;  or  by  ingestion  of  bacilli  from  the  intestinal  tract, 
passing  from  thence  to  the  lungs  by  the  lymphatics.  Appar- 
ently infection  takes  place  in  early  life,  prior  to  the  age  of  ten. 
The  disease  then  remains  latent  until  several  years  later,  until 
adolescence  or  early  adult  life. 

(h)  Methods  of  Control.  The  Injected  Individual. — i.  Diag- 
nosis: By  clinical  manifestations  and  bacteriological  examina- 
tion of  the  sputum. 

2.  Isolation:  Only  of  such  open  cases  that  do  not  observe 
the  precautions  necessary  to  prevent  the  spread  of  the  disease. 

3.  Artificial  Immunization:  None. 

4.  Quarantine:  None. 

5.  Concurrent  Disinfection:  Of  the  sputum  and  of  articles 
contaminated  therewith, 

6.  Terminal  Disinfection:  Cleaning  and  renovation  of  the 
occupied    quarters. 

General  Measures. —  i.  Education  of  the  public  regarding 
the  dangers  of  tuberculosis  and  the  necessary  measures  for 
its  prevention  and  control,  with  special  stress  laid  upon  the 
dangers  of  exposure  and  infection  in  early  childhood . 

2.  Provision  of  dispensaries  and  visiting  nurse  service  for 
the  discovery  of  early  cases,  and  the  supervision  of  home  cases. 

3.  Provision  of  hospitals  for  the  isolation  of  advanced  cases 
and  of  sanitaria  for  the  treatment  of  early  cases. 

4.  Provision  of  open-air  schools  for  pretubercular  children. 

5.  Improvement  in  housing  conditions,  particularly  dealing 
with  overcrowding,  inadequate  lighting  and  ventilation,  as  well 
as  improving  the  nutrition  of  the  poor. 

6.  The  ventilation  and  elimination  of  dust  in  industrial 
establishments  and  places  of  public  assembly. 

7.  Improvement  in  the  personal  hygiene  of  the  public,  parti- 
cularly preventing  promiscuous  expectoration,  and  a  betterment 
of  the  general  living  conditions. 

8.  Separation  of  babies  from  tuberculous  mothers  at  their 
birth. 

LEPROSY 

(a)  Injective    Agent. — Mycobacterium  lepra. 

{b)  Source  oj  Injection. — Probably  typical  and  atypical 
human  cases. 

(c)  Exit  oj  Injective  Agent. — In  the  discharges  from  nasal 
lesions  and  ulcerated  areas  elsewhere  on  the  body. 


66  PRACTICAL  PREVENTIVE   MEDICINE 

(d)  Routes  o]  Transmission. — By  close,  intimate  and  pro- 
longed contact  with  infected  persons,  and  possibly  by  insects. 

(e)  Incubation  Period. — Prolonged  and  unknown. 

(j)  Period  oj  Communicability. — Throughout  the  duration 
of  the  disease,  but  apparently  where  good  standards  of  hygiene 
prevail  this  disease  is  but  slightly  communicable.  The  disease 
may  in  some  cases  be  controlled  by  the  chalmoogra  oil 
treatment. 

(g)  Methods  of  Control.  The  Injected  Individual. — i.  Diag- 
nosis: By  clinical  manifestations  and  bacteriological 
examination. 

2.  Isolation:  Of  a  nominal  character,  approximating  that 
suitable  to  tuberculosis. 

3.  Artificial  Immunization:  None. 

4.  Quarantine:  None. 

5.  Concurrent  Disinfection:  Of  all  discharges  and  articles 
soiled  therewith. 

6.  Terminal  Disinfection:  Thorough  cleaning. 

General  Measures. — 1.  Provision  of  public  hospitals  for  the 
exclusive  care  of  lepers.  Under  suitable  conditions  of  en- 
vironment, together  with  a  proper  attitude  on  the  part  of  the 
patient,  he  may  be  allowed  to  remain  at  his  home  premises 
under  supervision. 

REFERENCES 

Rosexau:  Preventive  Medicine  and  Hygiene.     3rd  Ed.,  pp.  134-171;  197-199; 

304-308;  322-330. 
Epidemic  Cerebro-spinal  Meningitis.     Reprint  69,  Public  Health  Reports. 
Leprosy  in  the  United  States.     Reprint  84,  Public  Health  Reports. 
The  Spread  of  Tuberculosis.     Reprint  249,  Public  Health  Reports. 
The  Interstate  Migration  of  Tuberculous  Persons.     Reprints  265,  266,  269 

and  283,  Public  Health  Reports. 
Tuberculosis:    The     Municipal     Care    and   Supervision    of   the    Tuberculous. 

Reprint  282,  Public  Health  Reports. 
Tuberculosis:  Reprint  309,  Public  Health  Reports. 
Poliomyelitis:  Minimum  Requirements  for  its   Control.     Reprint  361,  Public 

Health  Reports. 
Poliomyelitis:  Reprint,  373,  Public  Health  Reports. 
Diphtheria:  Its    Prevention    and    Control.     Supplement     14,   Public   Health 

Reports. 


CHAPTER  IX 
DISEASES  FREQUENTLY  TRANSMITTED  BY  CONTACT 

As  previously  stated  this  group  includes  the  diseases  whose 
infective  agents  leave  the  body  chiefly  in  the  excrement,  i.e. ,  the 
feces  and   urine.     Thus  we  have  to  consider  the    following: 

Typhoid  and  Paratyphoid  fevers:  i.e.,  the  Enteric  fevers. 

Asiatic  Cholera. 

The  Dysenteries,  particularly  the  bacillary  and  amoebic 
forms. 

Hookworm  Disease. 

THE  ENTERIC  GROUP 

(a)  Injective  Agents. — Bacterium  typhosus,  Bacterium  para- 
typhosus  A,  Bacterium  paratyphosus  B. 

(b)  Source  of  Infection. — Typical  and  atypical  cases  and 
carriers. 

(c)  Exit  oj  Injective  Agents. — Principally  in  the  feces  and 
urine.  Of  lesser  importance  are  the  sweat,  sputum.,  human 
milk  and  pus. 

(d)  Routes  oj  Transmission. — By  direct  or  indirect  contact, 
also  by  water,  milk  or  dairy  products,  shell-fish  and  other 
raw  or  uncooked  foods  contaminated  with  excrement,  and 
through  mechanical  transmission  by  house  flies  (See  Fig.  3). 
These  other  routes  will  be  considered  in  detail  later. 

(e)  Incubation  Period. — From  7  to  23  days,  averaging  10 
to  14  days. 

(_/)  Period  oj  Communicability. — From  the  appearance  of  the 
prodromal  symptoms,  throughout  the  illness  and  relapses, 
during  convalescence,  and  until  the  excrement  is  bacteriologic- 
ally  found  to  be  free  of  the  bacillus.  Carriers  may  harbour  the 
organisms  for  a  long  period  of  years. 

(g)  Entrance  of  the  Infective  Agents  into  the  Body. — By  the 
mouth  to  the  intestinal  tract. 

(h)  Methods  of  Control.  The  Infected  Individual. — 1.  Di- 
agnosis: Clinical  manifestations,  confirmed  by  bacteriological 
examinations  of  the  blood,  feces,  and  urine;  and  by  the  Widal 
test. 

67 


68  PRACTICAL   PREVENTIVE    MEDICINE 

2.  Isolation:  In  a  fly  proof  room,  preferably  under  hospital 
conditions  for  such  cases  that  cannot  command  adequate 
sanitary  environment  and  nursing  care  in  their  homes. 

3.  Artificial  Immunization:  Bacterial  vaccines  have  given 
highly  satisfactory  results  as  a  prophylactic.  They  should  be 
employed  on  susceptibles  who  are  known  to  have  been  exposed 
or  who  are  suspected  of  being  exposed. 

Furthermore,  their  widespread  employment  among  the  popu- 
lation at  large  should  be  encouraged.  Best  evidence  of  their 
value  is  afforded  by  the  experience  of  the  American  and  other 
armies.  Thus  in  the  Maneuver  Division  of  the  U.  S.  Army 
at  San  Antonio,  Texas  in  the  summer  of  191 1,  with  a  mean 
strength  of  12,801  men,  all  vaccinated,  there  were  from  March 
iotli  to  July  10th,  only  two  cases  of  typhoid.  One  of  these 
cases  had  not  been  vaccinated,  the  other  had  not  completed 
the  course.  As  a  consequence  of  vaccination,  there  was  in 
the  period  between  1909  and  19 14,  only  one  death  from  typhoid 
in  the  army  (about  80,000  men),  while  the  death  rate  in  the 
country  at  large  averaged  over  16.5  per  hundred  thousand. 

The  immunity  varies  in  degree  and  also  in  duration,  though 
when  produced  by  a  series  of  inoculations  on  the  army  plan,  it 
probably  may  be  depended  upon  for  two  or  three  years. 

Combined  vaccines,  prepared  from  the  typhoid  bacillus  and 
the  alpha  and  beta  paratyphoid  bacilli  are  preferable,  of  which 
the  typhoid  bacillus  comprises  50  per  cent,  of  the  organisms  in 
suspension.  The  common  suspensions  have  approximately 
two  billion  dead  bacteria  per  c.c.  The  initial  dose  is  one  billion 
and  later  doses  two  billion  bacteria.  At  least  three  and  pre- 
ferably four  inoculations  should  be  given.  The  inoculations 
are  made  subcutaneously  at  the  point  of  insertion  of  the  del- 
toid, after  the  site  has  been  painted  with  tinture  of  iodine.  The 
inoculations  should  be  spaced  about  one  week  apart.  Most 
people  only  experience  a  local  reaction.  The  general  reaction, 
which  appears  within  twenty  fours  and  rapidity  subsides,  is 
never  serious  and  consists  of  malaise,  muscular  soreness  and 
fever. 

4.  Quarantine:  None. 

5.  Concurrent  Disinfection:  Of  all  bowel  and  urinary  dis- 
charges and  of  all  objects  contaminated  by  them. 

6.  Terminal  Disinfection:  Cleaning. 

General  Measures. — 1.  Purification  and  disinfection  of  public 
water  supplies. 

2.  Pasteurization  of  public  milk  supplies. 


DISEASES    FREQUENTLY    TRANSMITTED   BY   CONTACT  69 

3.  Supervision  of  food  supplies  and  of  persons  employed  as 
food  handlers. 

4.  Prevention  of  fly  breeding. 

5.  Sanitary  disposal  of  human  excreta. 

6.  Extension  of  the  public  immunization  by  vaccination  as 
far  as  practicable. 

7.  Recognition  of  typhoid  carriers  and  their  exclusion  from 
the  handling  of  foods  to  be  consumed  by  others. 

8.  Systematic  searches  for  carriers. 

9.  Exclusion  of  suspected  milk  supplies  pending  the  dis- 
covery of  the  person  or  other  cause  of  the  infected  condition  of 
the  milk. 

10.  Exclusion  of  a  water  supply  if  contaminated,  until  ade- 
quately treated  with  hypochlorite  or  other  disinfectant,  unless 
the  water  used  for  toilet,  cooking  and  drinking  purposes  is 
boiled  before  use. 

ASIATIC  CHOLERA 

(a)  Infective  Agent. — Spirillum  choleras, 

(b)  Source  of  Infection. — Typical  and  atypical  cases  and 
carriers. 

(c)  Exit  of  Infective  Agent. — In  the  bowel  discharges  and 
vomitus. 

(d)  Routes  of  Transmission. — By  direct  or  indirect  contact, 
by  food  or  water  contaminated  with  excrement  or  by  flies. 

(e)  Incubation  Period. — One  to  five  days,  usually  three,  oc- 
casionally longer  if  the  stage  of  incubatory  carrier  precedes 
the  onset. 

(/)  Period  oj  Communicability . — Usually  7  to  14  days  or 
longer,  and  until  the  vibrios  have  disappeared  from  the  bowel 
discharges  as  determined  bacteriologically.  Chronic  carriers 
are  not  uncommon. 

(g)  Entrance  oj  Injective  Agent  into  the  Body. — By  the  mouth 
to  the  intestinal  tract. 

(h)  Methods  of  Control.  The  Injected  Individual. — 1.  Di- 
agnosis: Clinical  manifestations,  confirmed  bacteriologically. 

2.  Isolation:  In  a  hospital  or  screened  room. 

3.  Artificial  Immunization:  Vaccination  is  still  in  the  ex- 
perimental stages. 

4.  Quarantine:  Contacts  should  be  detained  for  five  days 
from  the  date  of  their  last  exposure,  or  longer  if  one  is  found 
to  be  a  carrier. 

5.  Concurrent  Disinfection:  Of  the  stools  and  vomitus.     All 


70  PRACTICAL   PREVENTIVE    MEDICINE 

objects  probably  and  certainly  contaminated  should  be  dis- 
infected. Food  left  by  the  patient  should  also  be  disinfected. 
6.  Terminal  Disinfection :  Bodies  of  those  dying  from  cholera 
should  be  cremated  if  possible,  otherwise  wrapped  in  a  sheet 
saturated  with  a  disinfectant  and  buried  in  water  tight  caskets. 
The  isolation  quarters  should  be  thoroughly  cleansed  and 
disinfected. 

(a)  Attendants  must  protect  themselves  and  others  by 
rigid  attention  to  scruplous  cleanliness,  disinfection  of  the 
hands  each  time  after  handling  the  patient  or  touching  articles 
contaminated  by  dejecta,  the  avoidance  of  eating  or  drinking 
anything  in  the  room  of  the  patient,  and  should  be  prohibited  from 
entering  the  kitchen. 

(b)  The  bacteriological  examination  of  all  contacts  to  detect 
carriers,  and  the  isolation  of  those  found. 

(c)  Water  should  be  boiled  if  used  for  drinking  or  toilet  pur- 
poses, or  if  used  in  washing  dishes  or  food  containers,  unless  the 
supply  is  protected  against  contamination,  or  is  treated  by 
chlorination. 

(d)  Careful  supervision  of  food  and  drink.  When  cholera  is 
present  only  cooked  foods  should  be  eaten,  while  after  cooking 
its  contamination  either  by  flies  or  handling  should  be 
prevented. 

Epidemic  Measures. — The  following  measures  should  be  em- 
ployed in  emergencies. 

Inspection  service  for  the  early  detection  and  isolation  of 
cases;  the  examination  of  all  persons  exposed  to  cholera  in  in- 
fected centers  for  the  detection  of  carriers,  with  the  isolation  or 
control  of  those  discovered;  disinfection  of  the  rooms  occupied 
by  the  sick ;  and  the  temporary  quarantine  detention  in  suitable 
camps  of  those  desiring  to  leave  for  another  locality.  These 
before  leaving  should  be  examined  bacteriologically  to  detect 
possible  carriers. 

AMCEBIC  DYSENTERY 

(a)  Infective  Agent. — Entamceba  histolytica. 

(b)  Source  of  Infection. — Typical  and  atypical  cases  and 
carriers. 

(c)  Exit  of  Infective  Agent. — In  the  feces  and  bowel  discharg- 
es. 

id)  Route  of  Transmission. — By  direct  and  indirect  contact, 
and  by  food  or  drink  contaminated  with  bowel  discharges,  or 
by  flies. 


DISEASES    FREQUENTLY    TRANSMITTED   BY   CONTACT  7 1 

(e)  Incubation  Period. — Unknown. 

(/)  Period  oj  Communicability. — During  the  active  stage  of 
the  disease  and  as  lorg  as  cysts  are  discharged. 

(g)  Entrance  oj  Injective  Agent. —  By  the  mouth  to  the  intes- 
tinal tract. 

(h)  Methods  of  Control.  The  Injected  Individual.- — i.  Di- 
agnosis: Clinical  manifestations,  confirmed  by  the  detection  of 
trophozoites  and  cysts  in  the  stools. 

2.  Isolation:  None. 

3.  Artificial  Immunization :  None. 

4.  Quarantine:  None. 

5.  Concurrent  Disinfection:  Of  the  bowel  discharges  and 
articles  soiled  therewith. 

6.  Terminal  Disinfection:  Cleaning. 

General  Measures. — i.  Boil  the  drinking  water  unless  the 
supply  is  known  to  be  free  from  fecal  contamination. 

2.  Water  supplies  should  be  protected  from  fecal  contamina- 
tion, and  official  supervision  should  be  exercised  over  all  foods 
eaten  raw. 

BACILLARY  DYSENTERY 

(a)  Injective  Agent. — Bacterium  dysenteries,  all  types. 

(b)  Source  oj  Injection. — Typical  and  atypical  cases  and 
carriers. 

(c)  Exit  oj  Injective  Agent — .In  the  feces  and  bowel  discharges. 

(d)  Route  oj  Transmission. — By  direct  or  indirect  contact,  by 
contaminated  food  or  water,  and  by  flies. 

(e)  Incubation  Period. — From  two  to  seven  days. 

(/)  Period  oj  Communicability. — During  the  "dysenteric" 
period  of  the  disease  and  until  the  bacilli  are  absent  from  the 
bowel  discharges,  as  determined  bacteriologically.  Chronic 
carriers  may  develope. 

(g)  Entrance  oj  Injective  Agent. — By  the  mouth  to  the  intes- 
tinal tract. 

(h)  Methods  of  Control.  The  Injected  Individual. — i.  Di- 
agnosis: By  clinical  manifestations,  confirmed  by  serological 
tests  and  bacteriologic  examination  of  the  stools. 

2.  Isolation:  Of  infected  persons  until  they  no  longer  dis- 
charge the  bacilli. 

3.  Artificial  Immunization:  Vaccines  give  considerable  im- 
munity. Owing  to  severe  reactions  their  use  is  not  universal, 
nor  should  it  be  made  compulsory  except  in  an  extreme  emer- 
gency. 


72  PRACTICAL  PREVENTIVE    MEDICINE 

4.  Quarantine:  None. 

5.  Concurrent  Disinfection:  Of  bowel  discharges  and  all 
objects  soiled  therewith. 

6.  Terminal  Disinfection:  Thorough  cleaning. 

General  Measures. — 1.  Rigid  attention  to  personal  prophy- 
laxis by  the  attendants  upon  infected  persons. 

2.  No  milk  or  food  should  be  sold  from  premises  where 
exists  a  case  of  dysentery,  nor  should  the  patient's  attendants 
be  food  handlers  for  others. 

3.  Protection  of  drinking  water  by  boiling  or  chlorination, 
and  the  safeguarding  of  the  supply  from  fecal  contamination. 

4.  Protection  of  food  from  flies. 

We  next  have  to  consider  hookworm  disease  or  uncinariasis. 
It  is  questionable  whether  hookworm  disease  is  ever  spread  by 
contact,  hence  its  inclusion  in  this  group  is  not  proper.  How- 
ever it  does  have  one  characteristic  common  to  all  other  dis- 
eases of  this  group,  inasmuch  as  its  infective  agent  leaves  the 
body  in  the  feces.  Hence  its  consideration  here.  Hookworm 
infection  is  the  only  helminthic  infection  widespread  in  the 
United  States  and  producing  sufficient  systemic  disturbances  to 
demand  detailed  consideration. 

UNCINARIASIS  (HOOKWORM  DISEASE) 

(a)  Injective  Agent.- — Necator  americanus  and  Anchylo stoma 
duodenale. 

(b)  Source  oj  Infection. — Typical  and  atypical  cases  and 
carriers. 

(c)  Exit  oj  Injective  Agent.- — The  ova  are  discharged  in  the 
feces. 

(d)  Routes  oj  Injection. — By  fecal  contaminated  soil,  by 
contaminated  drinking  water,  and  possibly  by  direct  contact. 

(e)  Incubation  Period. — From  seven  to  ten  weeks. 

(/")  Period  of  Communic ability. — As  long  as  the  ova  are  passed, 
hence  as  long  as  the  patient  harbors  the  adult  worms. 

(g)  Entrance  of  the  Infective  Agent  into  the  Body. — Larval 
worms  present  in  the  soil  and  which  have  hatched  from  ova 
discharged  in  the  feces,  penetrate  the  skin  of  the  foot  between 
the  toes,  gain  access  to  the  circulation,  are  caught  in  the  pul- 
monary capillaries,  pass  into  the  pulmonary  alveoli,  go  up  the 
bronchi  to  the  larynx  and  down  the  oesophagus  to  the  intestine, 
or  are  ingested  with  contaminated  drinking  water.  Contami- 
nated soil  remains  infected  for  about  five  months  in  the  absence 
of  freezing. 


DISEASES    FREQUENTLY    TRANSMITTED   BY    CONTACT  73 

(h)  Methods  of  Control.  Infected  Person. — i.  Diagnosis: 
By  clinical  manifestations,  confirmed  by  the  microscopic  ex- 
amination of  the  feces. 

2.  Isolation:  None. 

3.  Artificial  Immunization :  None. 

4.  Quarantine:  None. 

5.  Concurrent  disinfection  of  the  feces 

6.  Terminal  Disinfection:  None. 

General  Measures. — i.  Installation  of  sanitary  privies  upon 
living  premises  and  the  education  of  people  in  their  proper  use. 

2.  The  safeguarding  of  domestic  water  supplies  from  fecal 
contamination. 

3.  The  wearing  of  shoes  outside  the  home. 

4.  The  treatment  of  infected  persons  by  thymol  and  oil  of 
chenopodium. 

REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene.     3rd  Ed.,  pp.  83-184. 
Sedgwick:  Principles   of   Sanitary  Science  and  Public  Health.     Chapter  VIII, 

pp.  164. 
Howard:  The  Control  of  Hookworm  Disease  by  the  Intensive  Method.     Pub. 

8.,  International  Health  Board. 
Antityphoid  vaccination.     Report  66,  Public  Health  Reports. 
Cholera:  Its   nature,   detection,   and  prevention.     Reprint  ^^,   Public  Health 

Reports. 
The  typhoid  bacillus  carrier :  a  review.     Reprint  58,  Public  Health  Reports. 
The  Bacteriological  Diagnosis  of  Cholera.     Reprint  75,  Public  Health  Reports. 
Hookworm    Disease:  The  use  of  Oil   of   Chenopodium.     Reprint   227,  Public 

Health  Reports 


CHAPTER  X 
GENERAL  MEASURES  OF  DISEASE  CONTROL 

There  are  fundamental  measures  underlying  the  whole 
problem  of  disease  control  to  some  of  which  we  have  previously 
referred.  Among  them  the  following  groups  may  be  distin- 
guished, the  first  two  of  which  will  be  considered  at  present. 
They  are  the  following: 

(a)  The  control  of  recognized  sources  of  infection. 

(b)  The  control  of  susceptible  contacts. 

(c)  The  destruction  of  insect  vectors. 

(d)  The   control  of  routes  of  infection  other  than  contact. 
The  last  two  of  these  will  be  considered  in  later  chapters. 

PROCEDURE  WITH  RECOGNIZED  OR  SUSPECTED  SOURCES  OF  IN- 
FECTION 

In  the  event  that  we  are  dealing  with  a  disease  of  the  lower 
animals,  the  work  is  much  simplified  by  the  prompt  destruction 
and  incineration  of  those  infected,  except  in  the  case  of  those 
which  have  a  high  monetary  value,  as  for  example  pedigreed 
or  highly  bred  livestock,  in  which  event  their  lives  may  be 
spared  and  the  same  measures  applied  to  them,  with  suitable 
modifications,  as  the  following  which  are  applied  to  human 
beings. 

(a)  Isolation. — By  isolation  we  mean  the  separation  of 
persons  suffering  from  a  communicable  disease,  or  carriers  of 
the  infecting  organism,  from  other  persons,  in  places  and 
under  conditions  that  prevent  the  direct  or  indirect  con- 
veyance of  the  infective  agent  to  other  persons.  The  degree 
necessary  to  accomplish  this  result  will  vary  with  different 
diseases,  as  indicated  in  the  previous  chapters. 

(b)  Quarantine. — By  quarantine  we  mean  the  limitation  of 
the  freedom  of  movement  of  persons  or  animals  who  have  been 
exposed  to  a  communicable  disease  for  a  period  of  time  equal 
to  or  slightly  greater  than  the  incubation  period  of  the  disease 
to  which  they  have  been  exposed.  It  implies  that  the  persons 
or  animals  to  be  supervised  are  susceptible  to  the  infection. 
The  limitations  necessary  are  of  varying  degree,  ranging  from  a 
mere  surveillance  to  an  actual  isolation. 

74 


GENERAL    MEASURES    OF    DISEASE    CONTROL  75 

CONDITIONS  OF  ISOLATION 

(a)  Isolation  should  be  continued  for  the  period  of  the  in- 
dividual's infectivity.  Its  termination  should  be  determined 
by  bacteriological  means  where  possible  or  practicable,  otherwise 
the  clinical  condition  of  the  individual  is  the  only  criterion, 
in  which  event  it  should  be  continued  until  complete 
convalescence. 

In  many  instances,  either  by  reason  of  the  economic  condition 
of  the  patient  or  his  family,  or  because  the  case  occurs  in  the 
person  of  a  transient,  it  is  impossible  to  isolate  the  patient  at 
his  dwelling.  In  this  event  it  is  necessary  to  effect  a  removal  of 
the  patient  to  some  place  where  satisfactory  isolation  may  be 
successfully  accomplished.  If  the  patient  is  to  remain  at  home, 
he  must  be  removed  to  a  room  or  suite  of  rooms  not  frequented 
by  other  members  of  the  family,  and  attended  by  an  individual 
who  gives  his  sole  attention  to  the  patient's  care.  Preferably, 
and  in  some  cases  necessarily,  the  attendant  must  be  a  trained 
nurse,  because  it  is  impossible  for  a  layman  to  suddenly  acquire 
a  subconscious  familarity  with  the  routine  of  isolation  pro- 
cedures. Under  no  circumstances  must  the  attendant  be  one 
who  prepares  food  or  food  stuffs  to  be  consumed  by  other 
persons  than  the  patient.  The  attendants  should  if  possible 
be  individuals  who  are  either  naturally  or  artificially  immunized 
to  the  disease  in  question. 

From  the  standpoint  of  the  patient's  cheer,  as  well  as  promot- 
ing natural  disinfection,  the  isolation  rooms  should  be  sunny, 
well  ventilated,  and  screened.  All  surplus  furnishings  should 
be  removed.  Within  the  room  should  be  placed  a  tub  of  disin- 
fectant solution  and  a  basin  of  a  suitable  disinfectant  should  be 
kept  on  a  stand  just  outside  the  door. 

All  of  the  members  of  the  family  and  visitors  should  be 
excluded.  The  only  visitors  permitted  should  be  the  attending 
physician  or  the  representative  of  the  health  authorities.  When 
entering  the  room  to  minister  to  the  patient,  the  attendant 
should  don  a  gown  that  protects  the  outer  clothing,  and  before 
leaving  the  room  thoroughly  wash  his  hands  in  the  disinfectant. 
Contaminated  objects  should  be  immersed  in  the  tub  of  disin- 
fectant before  their  removal.  The  general  precautions  to  be 
observed  by  the  attendant  will  be  discussed  later. 

Where  satisfactory  conditions  of  isolation  cannot  be  provided 
at  the  patient's  home,  that  individual  should  be  removed  else- 
where.    Large  cities  provide  special  isolation  hospitals  for  this 


76 


PRACTICAL   PREVENTIVE    MEDICINE 


purpose.  Small  communities  rarely  have  such,  facilities  and 
in  the  event  of  an  epidemic  frequently  isolate  patients  in  hos- 
pital tents. 

Isolation  hospitals,  as  at  present  constructed  are  of  two  types, 
namely  the  so-called  pavilion  plan  and  the  cubicle  plan. 

The  pavilion  plan  is  of  English  origin.  It  involves  the  classi- 
fication of  the  patients  upon  admission  according  to  their  ill- 
ness and  their  direction  to  separate  wards  or  pavilions  where  are 
segregated  all  patients  suffering  from  the  same  disease.  Each 
ward  or  pavilion  has  a  separate  staff  of  attendants.  In  a  large 
city  such  a  hospital  may  give  satisfactory  results  if  carefully 


a.- 


w^fc 


Fig.  5. — Gates  bedside  screen  in  use  at  Naval  Hospital,  Newport,  R.  I.  The 
screens  reduce  droplet  transference,  as  well  as  affording  greater  privacy.  (From 
Gates,  U.  S.  Naval  Med.  Bull.,  January,  1918.) 

operated,  but  several  disadvantages  exist.  First,  a  large  initial 
investment  to  build  the  separate  wards  or  pavilions  is  necessary, 
and  the  administration  is  not  flexible.  Second,  patients  ad- 
mitted may  already  be  incubating  a  second  disease,  or  a  mis- 
take in  a  diagnosis  may  have  been  made,  so  that  the  patients  in 
a  given  ward  are  exposed  to  a  second  infection,  and  the  newly 
admitted  patient  is  also  exposed,  so  that  re-infections  or  "  cross  " 
infections  are  not  unusual.  The  disease  is  the  unit  considered. 
The  cubicle  plan  is  of  French  origin,  having  been  developed 
in  the  hospital  of  the  Pasteur  Institute  by  Grancher.  As 
applied  the  character  of  the  institution  where  the  patients  are 
housed  is  of  secondary  importance,  the  feature  of  prime  im- 


GENERAL   MEASURES    OF   DISEASE    CONTROL  77 

portance  being  the  nursing  technique  employed.  This  is 
termed  medical  asepsis  as  contrasted  with  the  surgical  asepsis 
of  the  operating  room.  Its  effort  is  to  prevent  the  transfer  of 
infective  agents  from  one  patient  to  another.  The  patient  is 
the  unit  considered.  From  the  standpoint  of  hospital  operation 
the  aseptic  technique  aims  to  confine  each  different  infection 
to  a  physically  separate  unit.  The  patients  may  be  confined 
in  separate  rooms  or  be  in  wards.  In  the  latter  event  the  beds 
are  placed  at  least  six  feet  apart  and  separated  by  screens  to 
prevent  droplet  transference.  (Fig.  5).  Where  the  nursing 
staff  is  thoroughly  drilled  in  the  following  instructions,  cross 
infections  are  exceedingly  rare,  mistaken  diagnoses  do  not 
endanger  the  other  patients  and  the  elasticity  of  operation 
makes  the  expenses  much  lower.  The  success  however,  de- 
pends entirely  on  the  proficiency  of  the  nursing  staff  in  the 
aseptic  technique. 

PRINCIPLES  OF  ASEPTIC  TECHNIC 

The  nurses  wear  short  sleeved  uniforms  with  skirts  at  least 
five  inches  from  the  floor,  also  a  cap.  Large  gowns  are  worn 
by  nurses  and  doctors  only  when  in  intimate  contact  with 
patients.  The  sleeves  of  the  gown  extend  to  the  wrists  and  are 
confined  by  rubber  bands.  Before  entering  a  unit,  a  gown 
which  is  always  kept  hanging  outside  the  unit  when  not  in  use 
is  slipped  over  the  uniform,  and  when  leaving  the  gown  is 
removed  and  the  hands  immediately  scrubbed  in  a  disinfectant 
solution. 

The  following  rules  must  be  constantly  borne  in  mind  by  the 
nurses  and  attendants: 

(a)  Touch  nothing  pertaining  to  the  patient  except  with  your 
own  hands  and  then  scrub  the  hands  thoroughly.  Touch 
nothing  unnecessarily. 

(b)  Keep  fingers,  pencils,  pens,  labels  and  everything  of  that 
sort  out  of  your  own  mouth. 

(c)  Wash  your  hands  frequently  and  always  before  leaving 
a  unit  or  ward  or  before  eating. 

(d)  After  handling  a  patient  do  not  touch  your  face  until 
your  hands  are  washed. 

(e)  Do  not  allow  patients  to  cough  or  sneeze  in  your  face. 
(/)  If  rendering  an  intimate  service  it  is  best  to  wear  a  gauze 

mask  over  the  mouth  and  nose. 

(g)  Do  not  kiss  a  patient  or  allow  him  to  touch  your  face. 


78  PRACTICAL    PREVENTIVE    MEDICINE 

(h)   Do  not  eat  anything  a  patient  may  wish  to  give  you. 

(i)    Keep  and  use  only  your  own  drinking  glass. 

(j)   Remember  that  infections  are  spread  chiefly  by  contact. 

(k)  Never  lean  against  the  bed  or  furniture  in  the  unit. 

(I)  Always  take  into  a  unit  everything  required  to  serve 
the  patient  before  becoming  contaminated. 

The  foregoing  principles  are  just  as  important  in  home  as  in 
hospital  isolations. 

Isolation  in  the  case  of  biologically  transmitted  diseases 
is  effective  if  the  insect  vectors  are  absolutely  excluded  or 
destroyed. 

THE  VALUE  OF  MASKS 

In  our  opinion  masking  is  a  very  valuable  protective  measure 
against  any  of  the  acute  contact  transmitted   infections,  of 


W^  ,fl\ 

"•&#  ^9 

fli 

^y                            ^H 

1 

1 

W  ~^-.  '-M 

^^^  .,±**&^  ^*- 

Fig.  6. — Durand  hospital  mask,  devised  by  Miss  Charlotte  Johnson,  superin- 
tendent: The  gauze  (44  by  40  mesh)  is  cut  8  inches  wide  and  23  inches  long. 
The  sides  and  one  end  are  turned  down  one-quarter  inch.  It  is  folded  twice, 
the  unturned  end  first,  making  a  7}^-inch  square.  The  opposite  diagonal  corners 
are  cut  off  1  inch  and  the  raw  edge  is  turned  in  one-half  inch.  It  is  stitched 
firmly  all  around.  A  i-inch  dart  i^Ij  inches  long  is  taken  up  at  the  middle  of 
each  side  of  the  mask.  A  14-inch  tape  is  sewed  on  the  opposite  uncut  corners. 
This  mask  has  the  advantage  of  covering  the  nose  and  mouth  and  in  making  the 
traction  on  the  chin  and  not  drawing  on  the  nose  and  lips.  (From  Weaver,  Jour. 
Am.  Med.  Assoc,  71-17-     P-  1405.) 

greatest  value  as  a  protection  for  physicians,  nurses,  and  others 
in  close  contact  with  infected  persons,  as  well  as  a  measure  to 
be  recommended  to  the  public  as  a  protection  during  epidemics 


GENERAL   MEASURES    OF   DISEASE    CONTROL  79 

of  highly  contagious  virulent  infections.  Masks  possess  a  two 
fold  value.  Over  the  mouth  and  nose  of  an  infected  person 
they  reduce,  if  not  altogether  eliminate,  the  distribution  of  an 
infected  mouth  spray.  On  the  attendants  of  the  sick  or  the 
uninfected  populace  they  reduce  the  probabilities  for  inhalation 
of  infected  droplets,  as  well  as  serving  as  a  continuous  reminder 
that  the  fingers  should  be  kept  away  from  the  mouth.  In  order 
that  the  maximum  benefit  be  secured,  certain  definite  specifica- 
tions in  their  manufacture  should  be  observed,  and  the  masks 
should  be  changed  and  disinfected  at  intervals  of  three  or  four 
hours.  According  to  Weaver,  masks  made  of  three  layers  of 
absorbent  gauze,  of  a  mesh  of  forty-four  by  forty  are  satis- 
factory for  ordinary  use,  and  while  in  caring  for  very  virulent 
infections  six  layers  should  be  employed.  Masks  will  not 
prevent  the  introduction  of  infective  agents  into  the  nasal 
passages  via  the  lachrymal  ducts  or  conjunctivae.  It  may  be 
necessary  to  supplement  them  by  suitable  goggles  when  an 
individual  is  exposed  to  mouth  spray.  Their  construction  and 
adjustment  is  shown  in  Fig.  6. 

CONCOMITANT     DISINFECTION     (CONCURRENT     DISINFECTION) 

Effective  isolation  demands  the  careful  collection  of  all  the 
infective  discharges  as  soon  as  voided,  and  the  immediate  des- 
truction of  the  infective  agents  present,  or  of  objects  that  have 
been  contaminated  with  them,  before  their  removal  from  the 
isolation  quarters  or  the  unit.  This  is  known  as  concomitant 
disinfection.  It  is  essential  that  it  be  followed  out  in  a  careful 
and  systematic  manner.  If  the  regimen  of  concurrent  disinfec- 
tion has  been  carefully  followed  there  should  be  no  need  for 
gaseous  disinfection  at  the  termination  of.  the  isolation,  a 
thorough  cleaning  should  abundantly  suffice.  During  the 
stage  of  the  acute  illness  the  attendant  alone  can  carry  this  out. 
When  convalescence  is  established  it  will  be  necessary  to  in- 
struct the  patient  and  secure  his  co-operation. 

TERMINAL   DISINFECTION 

By  this  we  mean  the  process  of  rendering  the  clothing  and 
environment  of  the  patient  free  from  the  possibility  of  conveying 
infection  to  others  at  a  time  when  the  patient  is  no  longer  a 
source  of  infection,  or  we  may  also  apply  this  term  to  the  disin- 
fection of  the  premises  occupied  prior  to  the  death  of  the  patient, 


80  PRACTICAL   PREVENTIVE    MEDICINE 

or  his  removal  elsewhere  in  the  infective  period  of  his  illness.  In 
the  event  that  concurrent  disinfection  has  been  faithfully  carried 
out,  the  patient's  environment  will  undoubtedly  not  be  con- 
taminated and  a  prompt  cleaning  of  the  premises  by  scrubbing 
and  washing  will  be  adequate.  On  the  other  hand,  if  the 
patient  is  removed  from  the  premises  where  he  first  took  sick, 
or  early  death  has  occured  before  an  effective  regimen  of  con- 
comitant disinfection  had  been  established,  there  is  every 
reason  to  believe  that  the  quarters  are  contaminated,  and  then 
the  cleansing  may  be  supplemented  by  gaseous  disinfection, 
either  with  sulfur  dioxid  or  with  formaldehyde. 

THE  TERMINATION  OF  ISOLATION 

When  the  patient  is  deemed  to  be  no  longer  harboring  the 
infective  agent,  either  as  a  result  of  clinical  judgement  or  bacteri- 
ological examinations,  he  maybe  released  from  detention.  Prior 
to  this  a  thorough  bath  should  be  given  and  the  patient  dressed 
in  fresh  clothing.  He  may  then  be  removed  from  the  quarters 
of  his  detention  and  given  as  much  freedom  as  his  physical 
condition  warrants.  The  isolation  quarters  are  then  treated 
as  previously  described. 

SUCCESS  OF  ISOLATION 

As  a  public  health  measure  the  success  of  the  foregoing  me- 
thod in  reducing  the  prevalence  of  a  given  disease  will  be  in- 
versely proportional  to  the  number  of  unrecognized  infective 
persons  at  large.  If  the  latter  are  extensive  the  careful  isolation 
of  the  known  infective  persons  will  accomplish  little  in  the 
checking  of  an  epidemic.  On  the  other  hand,  from  the  stand- 
point of  checking  the  development  of  secondary  cases  in  the 
patients  household,  isolation,  even  under  the  latter  circum- 
stances should  be  carried  out.  Premature  release  of  patients 
from  isolation  is  indicated  by  the  development  of  the  so-called 
return  cases.  These  are  cases  arising  among  the  patient's  asso- 
ciates following  his  return  home.  Their  occurrence  always  call- 
for  a  re-examination  of  the  released  patient.  The  value  of 
isolation  according  to  different  degrees  of  care  observed  is  well 
shown  by  the  following  observations  of  G.  B.  Young  in  Chicago. 
Three  different  classes  of  isolation  in  the  home  were  made: 

A.  Isolation  with  a  trained  attendant. 

B.  Isolation  without  a  trained  attendant. 


GENERAL    MEASURES    OE    DISEASE    CONTROL  8 1 

C.  Isolation  in  the  home  impossible.  When  possible  cases 
in  this  class  were  hospitalzied. 

The  following  results  were  secured  with  scarlet  fever  and 
diphtheria. 

TABLE  III 
Diphtheria,  March  15,  1914  to  Nov.  1,  1914. 


No.  cases 

Susceptibles 

Secondary  cases 

Per  cent. 

A.  Isolation 

B.  Isolation 

C.  Isolation 

Hospitalized 

139 

5o8 

2,024 

656 

496 
2,279 
9^36 
1,903 

O 

6 

98 

1 

0.0 
1. 18 

4.88 
O    15 

Scarlet  Fever,  March  15,  1914  to  Nov.  1,  1914 


No.  cases 

Susceptibles 

Secondary  cases 

Per  cent. 

A.  Isolation 

B.  Isolation 

C.  Isolation 

Hospitalized 

92 
306 
870 
430 

112 

234 
865 

315 

I 
16 
60 
IO 

I.087 
5-22 
6.9 
2.32 

SUSCEPTIBLES 

Individuals  who  do  not  give  a  history  of  a  previous  attack 
of  the  disease  in  question  should  be  regarded  as  susceptibles 
and  also  those  whose  active  artificial  immunization  was  re- 
ceived prior  to  its  average  period  of  duration.  In  the  follow- 
ing diseases,  however,  one  attack  is  followed  by  a  permanent 
immunity,  namely:  plague;  typhoid  fever  (second  attacks  in 
only  about  2.4  per  cent).;  cholera;  small  pox  (second  attack 
rare) ;  chicken  pox  (second  attack  rare) ;  scarlet  fever  (second 
attacks  in  about  0.7  per  cent);  measles  (second  attack  un- 
common, but  less  rare  than  in  scarlet  fever) ;  yellow  fever,  typhus 
fever;  syphilis  (reinfection  rare  but  is  possible  if  a  cure  of  the 
preceding  infection  has  been  secured) ;  mumps  and  poliomyelitis. 
In  the  following,  on  the  other  hand,  the  active  immunity  is  more 
or  less  transitory,  so  the  probabilities  favor  susceptibility, 
namely:  gonorrhoea,  influenza,  glanders,  dengue  fever,  diph- 
theria (second  attack  in  0.9  per  cent,  of  cases,  while  0.01  anti- 
toxic unit  per  c.c.  of  circulating  blood  protects  (negative  Schick 
reaction)  relapsing  fever,  tetanus  and  tuberculosis. 


82  PRACTICAL   PREVENTIVE    MEDICINE 

Susceptibles  exposed  on  different  dates  should  not  be 
quarantined  together,  otherwise  some,  who  were  not  in- 
fected by  their  first  exposure,  may  become  infected  from  their 
quarantined  associates.  Concommitant  disinfection  should  be 
practiced.  Daily  search  for  prodromes  should  be  made  and 
upon  their  appearance  isolation  of  the  patient  should  be  inauga- 
rated.  Susceptible  contacts  should  be  given  active  artificial 
immunization  as  early  as  possible  and  passive  immunization 
where  special  circumstances  suggests  its  advisability. 

REFERENCES 

Control  of  communicable  diseases.     Reprint  436,  Public  Health  Reports. 
Weaver.     Journal  American  Medical  Association.     Jan.  12,  1918. 
Dotjst  and  Lyon:  Journal  American  Medical  Association.     Oct.  12,  1918. 


CHAPTER  XI 

GENERAL  MEASURES  OF  DISEASE  CONTROL 

(Continued) 

i.  Modern  methods  for  the  control  of  communicable  disease 
require  that  the  health  authorities  have  a  prompt  knowledge  of 
how,  when,  and  where  cases  of  these  diseases  are  occurring. 
With  this  information  efficient  officials  can  secure  results,  without 
it  their  efforts  are  of  little  value.  This  informati6n  is  secured 
from  various  sources  among  which  the  following  may  be  men- 
tioned : 

(a)  Notification  of  cases  by  physicians. 

(b)  Laboratory  reports. 

(c)  Reports  by  visiting  nurses. 

(d)  School  inspection. 

(e)  House  to  house  searches. 

(/)  Reciprocal  notification  from  other  health  authorities. 

(g)  Gossip  and  newspaper  clippings. 

(h)  Carrier  searches  and  searches  among  contacts. 

(i)  Householders  and  teachers  reports. 

The  foregoing  are  listed  very  nearly  in  their  importance  as 
sources  of  information,  the  first  of  these  being  the  most  important. 

2.  Physicians  Duties  in  the  Reporting  of  Disease. — This  duty 
is  a  legal  one  though  the  details  of  the  obligation  vary  in  dif- 
ferent political  units.  In  a  general  way  one  may  say  that  the 
responsibility  for  the  initiation  and  enforcement  of  control 
measures  is  one  of  the  health  authorities,  while  the  responsi- 
bilities of  the  physician  relate  to  the  care  of  the  patient.  In 
communities  where  health  work  is  poorly  organized  the  line  of 
demarcation  is  indefinite.  The  physician  is  an  important  source 
of  morbidity  information  to  the  health  authorities.  His  re- 
ports should  give  the  following  information:  they  should  be  in 
writing  (for  legal  reasons),  and  state  the  name,  age  and  sex  of 
the  patient,  his  address,  place  of  residence,  name  of  disease, 
occupation,  place  of  employment  or  school  attended,  and  the 
physician's  signature.  These  are.  usually  sent  to  the  Health 
Officer.  Reporting  should  be  required  as  soon  as  a  diagnosis  is 
reached  and  doubtful  cases  should  also  be  reported.  A  sepa- 
rate report  should  be  made  for  each  case. 

83 


84  PRACTICAL   PREVENTIVE    MEDICINE 

3.  The  Reportable  Diseases. — The  diseases  whose  notifica- 
tion is  required  differ  in  various  political  units.  They  usually 
include  a  greater  or  less  number  of  the  diseases  which  are  in- 
cluded in  the  standard  morbidity  law,  (though  the  inclusion  of 
some  is  of  doubtful  importance  from  the  standpoint  of  public 
health),  namely: 

Actinomycosis  Small-pox 
Acute  infectious  conjunctivitis  Syphilis 

Anchylostomiasis    (uncinaria-  Tetanus 

sis)  Mumps 

Anthrax  Paratyphoid  fever 

Cerebrospinal        meningitis.  Scarlet  fever 

epidemic  Plague 

Chicken  pox  Pneumonia,  acute  lobar 

Cholera  Poliomyelitis 

Gonorrhea  Rabies 

Leprosy  Rocky     Mountain      Spotted 

Malaria  Fever 

Measles  Trachoma 

Dengue  Trichiniasis 

Diphtheria  Tuberculosis,  pulmonary 

Dysentery,  amoebic  Tuberculosis,       other       than 

Dysentery,  bacillary  pulmonary 

Favus  Typhoid  fever 

German  measles  Typhus  fever 

Glanders  Whooping-cough 

Septic  sore  throat  Yellow  fever. 

4.  Prompt  reporting,  which  is  necessary,  depends  upon  the 
following: 

(a)  Realization  by  physicians  of  the  necessity  for  reporting 
cases  from  a  public  health  standpoint. 

(b)  Enforcement  of  statutes  and  ordinances,  etc;  requiring 
reporting. 

(c)  Provision  of  public  and  private  facilities  for  the  promo- 
tion of  early  diagnosis.  The  clinical  diagnosis  of  typical 
cases  is  fairly  easy,  but  atypical  cases,  exotic  diseases,  or  those 
whose  clinical  recognition  may  be  delayed,  will  have  to  be 
diagnosed  by  means  of  laboratory  assistance.  Hence  public 
laboratory  service  should  be  available  for  this  purpose. 

5.  Estimates  of  the  diseases  prevalence  are  of  value  to  the 
health  officer  for  the  purpose  of  checking  the  completeness  of 
the  morbidity  reports.  For  this  purpose  the  following  may 
be  employed: 


GENERAL   MEASURES    OF    DISEASE    CONTROL  85 

(a)  Percentages  or  ratios  secured  from  autopsy  returns. 

(b)  The  scrutiny  of  the  mortality  reports,  to  ascertain  if 
the  patients  dying  from  the  reportable  diseases  were  previously 
reported  during  life  as  cases. 

(c)  Estimates  based  upon  the  mortality  returns  by  the  use 
of  case-mortality  ratios.  Thus  the  mortality  from  typhoid 
fever  is  ordinarily  considered  to  be  10  per  cent,  and  if  10  deaths 
occured  during  a  given  period,  one  would  expect  that  in  the 
same  interval  there  had  occured  approximately  ioo  cases. 

(d)  One  of  the  most  useful  means  of  promptly  checking  the 
unusual  occurrence  of  disease,  that  is  of  recognizing  incipient 
epidemics  in  order  that  effective  control  measures  may  imme- 
diately be  inaugurated,  is  the  so-called  endemic  index.  The 
endemic  index  is  the  average  number  of  cases  occuring  in  a 
given  area  during  a  given  period  of  time,  in  each  of  five  con- 
secutive years  exclusive  of  epidemics.  The  average  secured  is 
used  for  comparative  purposes  with  the  number  of  cases  re- 
ported in  later  periods. 

6.  Reciprocal  Notification. — Present  day  means  of  trans- 
portation are  steadily  progressing  in  speed.  As  a  consequence 
a  person  infected  on  the  other  side  of  the  world  may  travel 
half  the  globe  before  the  expiration  of  the  period  of  incubation. 
Consequently  infective  agents  can  be  transported  great  dis- 
tances by  apparently  healthy  persons.  Furthermore  those 
who  are  actively  infected,  either  cases  or  carriers,  recognized  or 
unrecognized,  may  travel  about  evading  the  health  authorities 
and  spread  infective  secretions  in  their  path.  Health  officers 
can  secure  valuable  assistance  in  detecting  the  possible  spread 
of  infective  agents  by  travellers  from  distant  points,  by  keeping 
informed  of  the  prevalence  of  these  diseases  in  jurisdictions 
other  than  their  own.  In  the  United  States  a  knowledge  01  the 
prevalence  of  reportable  diseases  in  other  jurisdictions  may 
be  gained  from  the  Public  Health  Reports  published  weekly 
by  the  Federal  Public  Health  Service.  This  bulletin  also 
publishes  world  wide  summaries  of  the  occurrence  of  plague, 
cholera,  typhus,  and  small-pox,  which  latter  summaries  are  also 
published  in  the  Monthly  Bulletin  of  the  International  Office  of 
Public  Health  Hygiene,  published  in  French  from  Paris.  In 
addition  several  of  the  more  progressive  State  Boards  of 
Health  notify  other  health  jurisdictions  of  cases  of  reportable 
diseases  developing  within  their  bounds  in  recent  arrivals 
from  these  outside  jurisdictions.  By  this  means  sources  of 
infection  frequently  unknown  to  these  authorities  are  revealed. 


86  PRACTICAL   PREVENTIVE    MEDICINE 

7.  Investigation    of    Cases    Reported    or    Discovered. — It 

should  be  the  purpose  of  every  health  officer  to  endeavor  to 
discover  the  source  of  infection  responsible  for  every  case  of 
disease  recognized.  This  can  only  be  accomplished  by  an 
epidemiological  investigation  of  every  case  reported  imme- 
diately upon  receipt  of  the  report,  simultaneously  with  the 
inauguration  of  appropriate  control  measures.  The  inves- 
tigation should  have  the  following  scope  in  order  to  reveal  the 
desired  information,  and  of  course  its  scope  will  vary  depending 
upon  the  routes  of  transmission  possible  with  different  infective 
agents.     The  information  sought  should  include: 

(a)  Clinical  Data. — Previous  attacks  of  the  same  disease, 
date  first  felt  ill,  date  took  to  bed,  date  diagnosis  achieved, 
date  of  recovery  or  death,  and  other  special  information  illu- 
minating these  points. 

(b)  Possible  Sources  oj  Injection  or  Routes  oj  Injection  En- 
countered.— Contact:  Exposure  to  known  or  suspected  cases, 
other  similar  cases  at  school  or  place  of  employment,  similar 
cases  in  the  same  neighborhood  etc.,  or  in  the  same  family, 
household,  or  among  other  associates;  travel;  social  activities 
etc. 

Water,  milk  and  food  consumed.  Usual  and  unusual  sources 
of  supply,  at  home,  place  of  employment,  school,  or  travel  etc. 
Where  unusual  sources  of  supply  are  ascertained,  particular 
endeavor  must  be  made  to  localize  the  date  of  their  consumption. 

Flies  and  other  insects  in  relation  to  a  possible  source  of  in- 
fection as  well  as  from  the  standpoint  of  further  dissemination 
of  infection  from  the  patient. 

(c)  Opportunities  jor  Further  Spread  oj  Infective  Agents  jrom 
the  Patient. — Susceptibles  in  contact  with  patient  from  the 
probable  beginning  of  his  infectivity;  the  dates  upon  which 
isolation  and  concurrent  disinfection  were  begun;  the  dates 
upon  which  they  ceased;  and  the  hygiene  and  sanitation  of  the 
patient's  dwelling. 

A  form  used  for  the  investigation  of  typhoid  fever  is  shown 
on  pages  87-90. 

Upon  the  scope  and  detail  of  the  interrogations  will  largely 
depend  the  success  of  the  investigation  in  revealing  the  probable 
source  and  route  of  infection.  When  all  information  is  gathered 
from  the  several  cases  of  an  epidemic  it  must  be  subjected  to  a 
statistical  analysis  to  secure  information  relative  to  the  route  of 
infection  involved  and  the  probable  source  of  infection.  The 
investigation  will  also  result  in  the  discovery  of  missed  cases. 


GENERAL   MEASURES    OF   DISEASE   CONTROL  87 

THE  STATE  UNIVERSITY  OF  IOWA 

LABORATORIES  Case  No 


FOR  THE 


Town 


STATE  BOARD  OF  HEALTH     n  ;     ,  .  ,     . 

Date  of  interview. 
EPIDEMIOLOGICAL  DIVISION  Informant 

Intestinal  Infections  Inquiry  Disease 


(1)  IDENTIFICATION  DATA 

Name? ^Age? 

Nationality  ? .• Residence  when  taken   sick  ? 

From .to , , Previous  residence? 

Occupation  ? Place  of  business  ? 

How   long  ? Institution  attended  ? 

How  long?. Removed  to  hospital? 

Name  and  location  ? , 

Date  reported? By  whom?. Address?. 

(2)  CLINICAL  DATA 

Previous   health  ? Previous  attack  of  same  disease  ? . 

Date  first  felt  ill?, , .Nature  of  earliest  symptoms ? 


Date  stopped  work  or  school  ? Date  took  to  bed  ? 

Date  first  seen  by  a  physician  ? 

Nature  of  onset  ? , 

Temperature? Rose   spots? Enlarged   spleen? 

Diarrhoea? Character  of  stools? 

Frequency? ♦ 

Results  of  Widal? White  count? 

Results  of  bacterial   examination? » 

Condition  and  other  symptoms?. 


Diagnosis? When  made: 

Received   typhoid   vaccine? » .- When? 

Date  complete  convalescense? , Date  death?... 


88  PRACTICAL   PREVENTIVE    MEDICINE 

(3)  SOURCES  OF  INFECTION 
(A)  Personal  associations: 

(a)     No.  of  members  in  family  ? No.  of  occupants  of  house  ? 

Those  who  have  had  typhoid  (etc)?  When? 


(b)  Deaths  in  household  during  past  year  and  cause?. 

(c)  Newcomers  in  household  within  3  months  ? 


.Where  from?. 


Have  any  of  above  had  typhoid  (etc)  ? .When?. 


(d)     Servants   in   household? No.? Names? 

. ... .......For  how  long? 

Home  residence? Typhoid  (etc)  in  their  home?. 

Previous  attack  of  typhoid  (etc.)  in  previous  places  of  employment? 


{e)     Has  patient  been  in  contact  with  :- 


A  known  case  ? 

A  suspected  case? 

A  case  of  prolonged  fever  ? 

A  convalescent  case? • 

With  persons  in  contact  with  typhoid  (etc)?.. 

(b)    Sanitation  of  Residence  30  Days  Prior  to  Illness: 

Character  of  residence? Sewered? 

Water   closet?     Inside — outside — location? 

Privy? In  use? Condition  of  superstructure. 


Condition  of  vault  ? 

Disposal  of  night  soil? ..Well  on  premises?. 

In  use  ? • Relation  to  privy  ? 

Condition? - .• •. 

Bouse  screened? .Flies  present? , 


GENERAL    MEASURES    OF    DISEASE    CONTROL                    89 
Relative   abundance  ? General  impression  of  Sanitation  of  premises  ? 


Previous  ease  of  same  disease  in  house  ? When  ? 

Previous  case  of  same  disease  in  neighborhood  ? When  ? . 

(c)     Water  used  within  30  days  prior  to  illness: — 

Solely  ? Where  ? 

Principally  ? Where  ? 

Occasionally? Where? 

That  used  at  place  of  business  or  institution  attended  ? 

Ice  how  used?. Source? 

Soft   drinks? Where? 


Others  in  family  using  same  water  ? 

(D)     Dairy  products  used  for  30  days  prior  to  illness: 

Milk  used:     as  a  beverage? In  tea,  coffee  or  cocoa?. 

On  cereals  ? : Boiled  or  pasteurized  ? . . . 

Source? Loose  or  bottled? 

Other  sources  ? ' 

Ice  cream? Source? 


Butter? Source?. 

*j^y>  ,?/-<»/?   pi/rc  I)  trjej  e-f eretm   or    6(//?&r  ait /Ac  . 

Others  in  family  using  same  dairy  products  ? , . 


(E)     Other  f ood : . .  Meals  where  taken : 

Solely? 

Principally  ? ■ r _  j 

Occasionally  ? 

Banquets,  picnics,  excursions  or  other  gatherings  attended  where  food,  milk  or  water  consumed? 

Celery? Source? Lettuce? Source? Radishes? t 

Source? Oysters,  etc? Source? Cold  meats? , 

Salads ? Source? , 

; Other  foods? 

Others  in  family  who  partook  of  same  food  ? ■ 

Delicatessen  foods  eaten  ? Source  ? Nature  ? 

Do  servants  eat  same  food  as  family? , ._.., 


90  PRACTICAL   PREVENTIVE    MEDICLNE 

(F)     Out-of-town'  (with-in-town)  trips  witliin  30  days  prior  to  illness  ;■ 

Where  to?.... ;..     ..When? 

Route  taken?. . . » « . .  J  .Stops? 

Meals  taken? .Water?. Milk ? . 

What  else  eaten? -....., 

Place  stopped  at?... .."..... ..., Sanitary  condition? 

Places  visited ? , 

Where  to? , . When? 

Route  taken?.....,...., .......Stops? 

Meals  taken?..., Water?. Milk?. 

Place  stopped  at? .,..,.,,...., ....Sanitary  condition? 

Places  visited? .  -. . .......................... 

Known  contact  at  these  places?....... 

Others  of  family  who  made  same  trips? .• 

Sathing  or  swimming?....;....; 


(4).. CONCERNING  FURTHER  SPREAD 

Did  patient  continue  at  usual  work  while  feeling-Ill  (milk  and  food  handlers)  ? 

Disposal  of  discharges  during  this'  period  ? » 

Antityphoid  vaccination  of  contacts?, .;, No? 

Date  of  beginning  precautions  against  spread? , .-, 

Isolation  of  patient?: Effective:    Non-effective?    Disinfection  of  feces?. 

, Urine?. , 

Manner  of  disposal  of  excreta  at  present?. , 

Screening  of  patient's  bedroom  ? Other  prophylactic  measures  ? 


Kurse:    trained  or  lay? Name ,  . 

Date  of  relaxing  precautions? ^. Condition  of  infectiveness  or  discharge? 


Investigator. 


GENERAL   MEASURES    OF   DISEASE    CONTROL  9 1 

8.  Analysis  of  Epidemiologic  Data. — In  undertaking  such  an 
analysis  it  is  important  to  locate  the  cases  both  from  the  stand- 
point of  place  and  time,  as  this  will  yield  important  information. 

First  however,  the  imported  cases  should  be  excluded  from 
the  analysis.  A  case  is  regarded  as  if  imported  if  either  (a) 
brought  into  the  local  area  while  ill,  or  (b)  if  out  of  town  at 
at  the  probable  time  infection  was  received.  The  principal 
consideration  they  should  receive  will  relate  to  their  potentia- 
lities as  a  local  source  of  infection. 

To  localize  the  cases  from  point  of  space  they  should  be 
plotted  upon  a  map  of  the  district  according  to  their  place  of 
illness  at  the  time  of  onset.  One  should  then  note  if  their  dis- 
tribution is  localized  or  generalized,  and  if  it  has  any  definite 
relation  to  possible  neighborhood  activities,  or  water  or  milk 
supplies.  From  the  standpoint  of  time  the  case  should  be 
plotted  upon  co-ordinate  paper  according  to  their  dates  of  onset. 
From  the  curve  thus  secured  one  should  note  whether  the 
course  of  the  epidemic  is  abrupt  or  explosive  in  its  rise  and  fall, 
or  slow  and  gradual.  The  former  curve  indicates  that  the  cases 
owe  their  infection  to  the  use  of  some  common  route  of  infec- 
tion, such  as  water,  milk,  etc.,  in  other  words  that  their  infec- 
tion has  been  simultaneous.  The  slow  rise  and  fall  of  the  curve 
indicates  contact  transmission  or  fly  transmission. 

The  contact  transmitted  diseases  with  short  incubation 
periods  and  great  virulence,  such  as  influenza,  will  produce 
an  epidemic  curve  much  more  abrupt  than  that  produced 
by  the  other  diseases  of  this  group,  having  longer  incubation 
periods. 

If  the  curve  is  explosive,  analysis  of  the  data  secured  under 
the  heading  of  probable  routes  of  infection,  should  be  made  to 
ascertain  the  route  of  infection  common  to  all  cases,  at  least 
those  of  the  explosive  period.  When  ascertained  this  must  be 
further  investigated  to  reveal  the  source  from  which  the  route 
became  contaminated. 

On  the  other  hand,  if  the  outbreak  had  a  slow  rise  and  fall 
the  contact  histories  will  for  the  most  part  link  up  with  one 
another,  excepting  for  gaps  produced  by  transfers  of  infective 
agents  from  unrecognized  infective  persons.  Epidemics  due  to 
different  types  of  routes  of  infection  have  certain  peculiarities, 
to  which  attention  will  be  called  when  considering  these  routes 
in  detail. 

As  soon  as  the  infected  route  of  transmission  is  ascertained 
proper  measures  to  render  it  innocuous  must  be  immediately 


92  PRACTICAL   PREVENTIVE    MEDICINE 

inaugurated.     When  this  is  done  the  epidemic  will  draw  to  a 
close  except  perhaps  for  a  few  scattered  contact  cases. 

The  probable  time  of  infection  is  reckoned  by  subtracting  the 
average  incubation  period  from  the  date  of  onset. 

9.  Emergency  and  Routine  Epidemiology. — Emergency  epi- 
demiology is  the  application  of  the  principles  presented  in  the 
foregoing  paragraphs  and  chapters  in  the  face  of  the  emergency 
produced  by  an  epidemic,  and  epidemics  usually  result  from  a 
deficient  or  inadequate  public  health  organization.  The  work 
is  usually  done  in  the  face  of  the  epidemic,  actually  at  a  time 
when  the  danger  is  at  a  maximum  or  tending  spontaneously  to 
decline.  The  remedial  measures  employed  are  usually  of  a 
temporary  character,  aiming  principally  at  a  control  of  routes 
of  infection  rather  than  sources. 

On  the  other  hand,  the  routine  application  of  the  foregoing 
methods  day  after  day  to  each  case  of  communicable  disease 
recognized,  will  soon  show  results  in  a  reduction  of  both 
morbidity  and  mortality,  and  extensive  epidemics  will  be 
prevented.  Small  epidemics  may  occur  due  to  unrecognized 
importations  of  infection,  but  these  will  not  have  a  chance  to 
spread.  This  is  routine  epidemiology,  which  not  only  aims  at 
a  permanent  control  of  the  routes  of  infection,  but  of  the 
sources  as  well. 

10.  Education  of  the  Public  in  General  Cleanliness. — The 
education  of  people  in  personal  hygiene  will  do  much  to  pre- 
vent the  spread  of  diseases,  as  well  as  secure  their  co-operation 
with  health  officials.  The  following  points  in  general  cleanliness 
are  of  special  importance  in  this  connection : 

(a)  Washing  the  body  frequently  with  soap  and  water. 

(b)  Washing  the  hands  with  soap  and  water  after  voiding  the 
bowels  and  bladder,  and  always  before  eating. 

(c)  Keeping  the  hands  and  unclean  articles,  or  articles  that 
have  been  used  for  toilet  purposes  by  others,  away  from  the 
mouth,  nose,  eyes,  ears  and  vagina. 

(d)  Avoiding  direct  exposure  to  the  spray  from  the  noses  and 
mouths  of  people  who  cough  and  sneeze,  or  laugh  and  talk 
loudly  or  in  an  explosive  manner. 

(e)  Avoiding  the  use  of  common  or  unclean  eating,  drinking, 
or  toilet  articles  of  any  kind,  such  as  towels,  hair  brushes,  drink- 
ing cups,  pipes  etc. 

(/)  In  epidemic  periods  public  assemblages  should  be  dis- 
couraged and  the  wearing  of  masks  should  be  encouraged. 
(g)  Promiscuous  spitting  should  be  prohibited. 


GENERAL    MEASURES    OF    DISEASE    CONTROL  93 

REFERENCES 

Barry:  Aseptic  Nursing  of  Infectious  Diseases.     American  Journal  of  Nursing. 

1916,  XVI,  pp.  8. 
Crowe:  Aseptic  Technique  Method  for  Contagious  Hospitals.     Journal  Michi- 
gan State  Society,  1916,  XV,  p.  5. 
Curtis:  Nursing  in  Contagious  Diseases.     The  Modern  Hospital,   1914,   11, 

p.  127. 
Schmidt:  Hosipitals  for  Communicable  Diseases  (with  bibliography). 

The  Modern  Hospital,  1918,  X,  pp.  153. 
A  Model    State   Law  for    Morbidity   Reports.     Reprint    133,   Public  Health 

Reports. 
Morbidity  Reports :  Their  importance  to  the  local  health  officer  and  his  work. 

Reprint  153,  Public  Health  Reports. 
Brooks  and  Godfrey:  The  prevention  and  control  of  communicable  diseases. 

New  York  State  Department  of  Health.     1919. 


CHAPTER  XII 
DISINFECTANTS  AND  DISINFECTION 

The  importance  of  disinfection  in  connection  with  isolation 
permits  this  subject  to  be  considered  to  best  advantage  at 
this  time. 

Disinfection  may  be  denned  as  the  destruction  of  infective 
agents  where  ever  they  may  be;  while  disinfectants  are  agents 
capable  of  producing  disinfection.  Disinfection  is  not  neces- 
sarily the  same  as  sterilization,  by  which  process  we  mean  the 
certain  destruction  of  all  forms  of  life. 

i.  Disinfectants  in  Relation  to  the  Body. — In  relation  to  the 
body  disinfectants  may  be  either  internal  or  external. 

(a)  Internal  disinfectants  are  employed  chiefly  as  therapeutic 
agents,  though  some  endeavor  has  been  made  to  employ  them 
in  the  sterilization  of  carriers.  Their  employment  is  the  basis 
of  specific  therapy  as  applied  to  infection.  As  examples  one 
may  site  the  employment  of  mercurials  and  arsensicals  in 
syphilis,  of  quinine  in  malaria,  of  ipecac  in  amoebic  dysentery 
and  ethyl-hydro-cuprein  in  lobar  pneumonia. 

(6)  External  disinfection  is  the  practice  in  which  we  are  at 
present  interested.  It  is  employed  upon  infective  agents  with- 
out the  body  under  the  following  circumstances: 

i.  As  they  leave  the  body  in  the  infective  secretions  and 
excretions. 

2.  After  they  have  been  distributed  in  the  environment  of  the 
patient. 

3.  After  they  have  gained  access  to  their  definitive  (insect) 
host. 

2 .  Disinfecting  Agencies  may  be  Either  Natural  or  Artificial. 
— We  may  perhaps  best  consider  them  according  to  whether 
their  action  is  physical  or  chemical. 

(a)  Physical  Disinjectants. — The  natural  agencies  of  disin- 
fection are  for  the  most  part  physical  in  character  and  com- 
monly their  importance  is  sadly  ignored.  Their  efficiency  is 
undoubtedly  the  principle  reason  for  the  salvation  of  most 
higher  organisms  from  the  ravages  of  the  lower  parasites,  as 
witness   the  extraordinary  numbers  of  these  which   are  dis- 

94 


DISINFECTANTS    AND    DISINFECTION  95 

charged  from  the  infected  host  while  so  few  succeed  in  reaching 
a  new  host.  Most  of  these  countless  parasites  are  doomed 
to  certain  destruction  by  these  natural  agencies  (see  Table  II, 
page  30).     The  physical  agencies  include  the  following: 

1.  Dessication. 

2.  Heat,  either  in  the  form  of  dry  or  moist  heat,  or  complete 
incineration.  Moist  heat  may  be  artificially  employed  either 
as  boiling  water,  streaming  steam,  or  steam  under  pressure. 

3.  Light:  particularly  sun  light,  and  of  the  sun's  rays  the 
ultra-violet  are  those  of  greatest  bactericidal  action. 

(b)  Chemical  Disinjectants. — Most  of  the  artificial  methods, 
particularly  these  employed  in  connection  with  medical  asepsis 
in  isolation  are  of  this  group.     These  are  either: 

1.  Liquids,  which  in  turn  are  either: 

Solutions,  such  as  bichloride  of  mercury,  phenol,  formalin, 
iodin,  chlorin,  bleach,  etc.,  or  suspensions,  such  as  the  cresol 
compounds. 

2.  Gases,  such  as  sulphur  dioxide  or  formaldehyde.  The 
employment  of  gaseous  disinfectants  is  known  as  fumigation. 

3.  Manner  of  Action. — Different  agencies  exert  their  lethal 
action  in  different  ways.  Some  of  the  lethal  effects  are  known, 
but  our  knowledge  of  the  means  of  their  action"  is  obviously 
incomplete.     Among  these  we  may  consider  the  following: 

(a)  Abstraction  of  water,  i.e.,  dessication.  This  may  be 
lethal  to  some  organisms,  or  cause  others  to  enter  upon  a  con- 
dition of  suspended  activity. 

(b)  Coagulation  of  the  protein  of  the  micro-organisms,  either 
with  or  without  an  ionic  poisoning  of  their  protoplasm.  The 
first  is  produced  by  the  action  of  metallic  salts,  while  such  agen- 
cies as  phenol  do  not  produce  an  ionic  poisoning. 

(c)  Destruction  by  emulsoid  action.  The  lethal  effect  is  due 
to  a  molecular  bombardment  of  the  micro-organism  by  the 
finely  suspended  particles,  associated  with  a  certain  amount  of 
poisoning  through  absorption. 

(d)  Oxidation  of  the  protoplasm,  such  as  that  produced  by 
ozone,  chlorine,  or  the  permanganates. 

4.  Standardization  of  Disinfectants. — Accurate  comparisons 
of  the  efficiency  of  disinfectants,  parlicularly  of  their  efficiency 
under  conditions  of  actual  employment  is  very  difficult,  due  to 
the  absence  of  suitable  standards.  Laboratory  experimenta- 
tion together  with  empirical  experience  has  demonstrated  the 
effectiveness  and  reliability  of  the  disinfectants  in  the  dilutions 
later  named.     It  is  when  one  is  called  upon  to  express  an  opin- 


96  PRACTICAL  PREVENTIVE  MEDICINE 

ion  as  to  the  use  of  some  proprietary  preparation  of  uncertain 
strength  and  composition,  that  the  greatest  need  of  such  standards 
is  felt.  While  some  progress  has  been  made,  in  the  comparison 
of  the  relative  efficiency  of  these  substances,  the  question  of 
standarization  is  still  far  from  settled.  This  is  chiefly 
due  to  the  great  number  of  factors  which  influence  the  activity 
of  disinfectants,  the  different  conditions  under  which  they  must 
act  in  practical  employment,  and  the  species  of  infective  agent 
upon  which  they  may  have  to  act.  The  most  important  ad- 
vance in  this  direction  was  the  method  introduced  by  Rideal 
and  Walker,  of  which  other  recent  methods  such  as  the  Hy- 
gienic Laboratory  method  are  modifications.  In  the  deter- 
mination time  of  action  and  temperature  of  exposure  are 
arbitrarily  taken  as  constants  and  the  strength  of  the  disin- 
fectant solutions  as  the  variable.  Phenol  has  been  chosen  as 
an  arbitrary  standard.  Cultures  of  B.  typhosus  in  broth  have 
commonly  been  employed  as  the  test  organism.  In  practice 
varying  dilutions  of  the  standard  phenol  are  compared  with 
varying  dilutions  of  the  unknown  disinfectant  being  tested, 
until  dilutions  of  the  two  are  found  which  kill  after  the  same 
period  of  exposure,  usually  arbitrarily  taken  at  seven  minutes. 
The  results  are  expressed  by  dividing  the  lowest  dilution  of  the 
unknown  by  the  lowest  dilution  of  phenol  which  killed  in  the 
same  space  of  time.  The  result  is  called  the  carbolic  coefficient 
of  the  unknown.  A  low  carbolic  coefficient,  expressed  as  a 
number  less  than  unity,  usually  means  the  substance  possesses 
slight  disinfecting  value.  On  the  other  hand,  the  possession  of 
a  high  coefficient  does  not  necessarily  mean  a  substance  is  suit- 
able for  practical  use.  Other  factors  must  be  taken  into 
consideration. 

5.  Properties  of  an  Ideal  Disinfectant  for  External  Use. 
We  can  specify  certain  properties  which  an  ideal  disinfecting 
substance  should  possess,  but  unfortunately  we  possess  no  dis- 
infectant in  which  all  these  properties  are  simultaneously  pres- 
ent.    They  are  the  following,  and  their  importance  is  self-evident : 

(a)  It  should  work  effectively,  i.e.,  disinfect,  with  or  without 
the  presence  of  organic  matter. 

(b)  It  should  be  reasonably  stable  from  a  chemical  stand- 
point. 

(c)  It  should  be  soluble  or  miscible  in  water. 

{d)  It  should  be  harmless  to  man  or  higher  animals  while 
highly  toxic  to  micro-organisms. 

(e)  It  should  possess  great  powers  of  penetration. 


DISINFECTANTS    AND    DISINFECTION  97 

(/)  It  should  not  corrode  metal,  bleach  pigments,  or  rot 
fabrics. 

(g)  It  should  be  commonly  available  at  a  reasonable  price. 
(h)  It  should  be  effective  against  all  infective  agents. 

6.  Conditions  Influencing  the  Efficiency  of  Disinfectants. — {a) 
Strength  of  solution  employed:  As  a  general  rule  the  activity 
of  disinfectants  is  directly  proportional  to  their  concentration, 
while  very  potent  substances  may  be  so  highly  diluted  that  they 
are  without  effect. 

(b)  The  length  of  time  in  which  they  are  permitted  to  act:  No 
disinfectant,  with  the  possible  exception  of  incineration,  is  in- 
stantaneous in  its  action  od  all  the  infective  agents  present  in  a 
given  medium.  An  appreciable  length  of  time  must  elapse 
for  its  effect  to  be  achieved. 

(c)  Certain  agencies  exert  what  is  known  as  a  selective  ac- 
tion. That  is  they  are  lethal  for  some  micro-organisms  but 
without  action  on  others.  Therefore  one  must  use  a  certain 
amount  of  discretion  in  the  selection  of  a  disinfectant  for  the 
destruction  of  a  given  parasite. 

(d)  The  material  to  be  disinfected  may  influence  the  results 
in  several  ways.  First,  organic  matter  may  afford  a  mechanical 
protection  for  the  infective  agents  and  thus  defeat  our  purpose, 
or  there  may  be  a  chemical  combination  between  the  disin- 
fectant and  other  substances  present,  as  a  result  of  which  the 
effective  quantity  of  our  agent  is  seriously  reduced.  Or  lastly, 
the  material  may  contain  resistant  stages  of  the  micro-organ- 
isms, such  as  spores,  which  are  not  readily  affected  by  the  agen- 
cies of  disinfection  selected. 

While  it  is  theoretically  possible  to  estimate  the  necessary 
quantities  of  disinfectant  to  apply  in  any  given  case,  yet  in 
practice  it  is  difficult  to  estimate  the  effect  of  the  foregoing 
factors,  since  they  are  extremely  variable.  Hence  in  practice 
disinfectants  must  be  employed  in  excess  quantities. 

7.  Technic  of  Concurrent  or  Concommitant  Disinfection. 
The  number  of  substances  suitable  for  the  purpose  is  not  large, 
if  we  select  those  which  most  nearly  possess  our  ideal  properties. 
The  following  solutions  may  be  considered  standard. 

(a)  For  the  disinfection  of  feces  and  urine  the  following  may 
be  used : 

1.  Formalin  in  10  per  cent,  solution.     Mix  equal  volume  of 
this  solution  with  the  excreta  and  allow  to  stand  for  one  hour. 
This  is  very  effective,  but  the  irritating  fumes  prevent  its  use 
in  the  sick  room. 
7 


98  PRACTICAL   PREVENTIVE    MEDICINE 

2.  Phenol  in  5  per  cent,  solution.  Mix  equal  volume  of  this 
solution  with  the  excreta  and  allow  the  mixture  to  stand  for  one 
hour. 

3.  Unslaked  Lime. — Add  a  quantity  of  unslaked  lime  of 
approximately  equal  volume  to  the  excreta  and  mix  well  by 
means  of  a  small  stick.  Cover  with  1  to  2  quarts  of  boiling 
water  and  allow  the  mixture  to  stand  for  two  hours.  This  is 
one  of  the  cheapest  methods. 

4.  Chlorinated  lime,  in  3  per  cent,  solution.  One  must  be 
sure  that  the  preparation  is  fresh,  otherwise  its  strength  will 
be  greatly  reduced  by  loss  of  the  chlorine.  Mix  equal  volumes 
of  excreta  and  the  solution  and  allow  to  stand  for  one  hour. 

5.  Liquor  cresolis  compositus  in  2  per  cent,  solution.  This  is 
one  of  the  cheapest  and  best  substances  for  this  purpose.  Mix 
equal  volumes  of  the  excreta  and  disinfectant  and  allow  to  stand 
for  one  hour. 

6.  The  foregoing  will  prove  satisfactory  for  the  destruction  of 
bacterial  infective  agents  in  the  feces,  but  will  not  destroy 
protozoan  parasites  or  helminth  ova.  According  to  Dr.  C.  W. 
Stiles  either  3  per  cent,  sodium  hydroxide  or  four  tenths  per 
cent,  sodium  dichromate  may  be  used  to  destroy  protozoan 
parasites  or  helminth  ova.  Most  species  are  killed  relatively 
soon  by  this  treatment,  but  the  ova  of  Ascaris  or  Oxyuris  may 
require  from  four  to  six  days  exposure  before  they  are  destroyed. 

(b)  For  the  disinfection  of  discharges  from  the  mouth  and 
nose. 

Undoubtedly  the  simplest  method  of  handling  these  secre- 
tions is  to  collect  them  on  old  rags  or  paper  napkins,  or  in  spu- 
tum cups,  and  incinerate  these  when  filled.  When  using  cloths 
or  napkins  the  patient  shuld  be  instructed  to  carefully  fold  in 
the  contaminated  area  so  that  contamination  of  the  fingers  is 
reduced.  Any  of  the  substances  recommended  for  the  dis- 
infection of  feces  and  urine  may  also  be  used. 

(c)  For  the  disinfection  of  bed  linen  and  clothing,  bed  pans 
and  other  contaminated  objects,  immersion  for  one  hour  in  the 
foregoing  solution  of  chlorinated  lime  or  liquor  cresolis  com- 
positus is  satisfactory. 

Dishes  should  be  received  into  a  dish  pan  kept  for  this  pur- 
pose, covered  with  water  and  boiled  before  washing.  Food 
remnants  should  be  incinerated. 

8.  Employment  of  Fumigants. — These  are  most  commonly 
employed  in  connection  with  terminal  disinfection.  Various 
proprietary  generators  are  on  the  market  for  the  liberation  of 


DISINFECTANTS    AND   DISINFECTION 


99 


both  formaldehyd  and  sulphur  dioxid,  but  the  only  advantage 
that  may  be  credited  them  is  that  of  convenience.  Most  of 
these  proprietary  formaldehyd  generators  liberate  the  gas 
from  paraformaldehyd  or  paraform,  the  solid  polymer  of 
formaldehyd. 

(a)  Formaldehyd  is  the  most  satisfactory  fumigant  available. 
Successful  results  depend  upon  the  rapid  liberation  of  the  gas 
from  either  formalin,  (its  40  per  cent,  aqueous  solution)  or 
solid  paraformaldehyd.  It  accomplishes  a  surface  disinfec- 
tion and  kills  spores,  though  its  action  on  them  is  slow  and  uncer- 
tain. It  does  not  tarnish  or  corrode  metal  or  bleach  pigments. 
It  is  not  an  insecticide.  For  successful  results  proper  condi- 
tions of  heat  and  moisture  are  necessary.     The  quarters  to  be 


Fig.  7. — Flaring  top  tin  bucket  for  generating  formaldehyd  by  the  perman- 
ganate method.  Height  15  inches,  diameter  10  inches  at  base,  15  inches  at 
top  of  flare.      (From  Register  "Fever  Nursing.") 


disinfected  must  be  maintained  at  a  temperature  of  '65  degrees 
F.  or  higher  and  the  relative  humidity  must  be  60  per  cent,  or 
higher.  The  following  methods  may  be  used  for  its  liberation: 
1.  Spray  the  formalin  upon  moistened  sheets  spread  out  over 
stretched  lines.  Use  at  least  eight  ounces  of  formalin  for 
every  1000  cubic  feet  in  the  apartment.  One  ordinary  bed 
sheet,  when  previously  moistened,  will  retain  this  amount  of 
the  formalin:  The  gas  is  liberated  by  the  evaporation  of  the 
water.     This  is  the  simplest  and  cheapest  method  available. 


IOO 


PRACTICAL    PREVENTIVE    MEDICINE 


2.  The  liberation  of  formaldehyd  by  means  of  potassium 
permanganate. 

(a)  This  method  was  widely  employed  when  potassium  salts 
were  cheap.  A  deep  flaring  can,  or  a  large  crock  or  jar  is  put 
in  a  tub  in  the  apartment  to  be  disinfected  (Fig.  7).  In  the 
crock  is  placed  250  grams  of  potassium  permanganate  for  every 
1000  cubic  feet  of  space  and  when  preparations  are  completed 
there  is  poured  over  this  500  c.c.  of  40  per  cent,  formalin  diluted 
with  an  equal  value  of  water,  for  every  1000  cubic  feet  of  space. 
The  operator  then  makes  a  hasty  exit.  The  crock  and  tub 
should  not  be  placed  near  any  draperies  and  the  floor  about 


Fig.   8. — Showing  the  pot  method  of  burning  sulphur. 

the  tub  had  best  be  protected  by  paper.     The  gas  should  act  for 
at  least  8  hours. 

(b)  Sulphur  dioxid  is  a  poorer  germicide  than  formaldehyd, 
but  is  a  good  mammalicide  and  insecticide.  It  posesses  several 
disadvantages,  namely  it  tarnishes  and  corrodes  metals,  bleaches 
pigments  and  rots  fabrics.  However  it  is  cheap  and  readily 
obtainable.  The  actual  disinfection  is  accomplished  by  sul- 
phurous acid,  for  whose  formation  water  vapor  is  necessary. 
Consequently  attention  must  be  given  to  humidity  conditions, 
although  moisture  is  not  necessary  when  it  is  used  as  an  insec- 
ticide. For  disinfecting  purposes  5  pounds  of  sulphur  for 
every  1000  cubic  feet  are  required.     This  is  equivalent  to  5  per 


DISINFECTANTS    AND    DISINFECTION 


IOI 


cent,  of  gas,  the  maximum  concentration  possible  in  the  air. 
For  every  5  pounds  of  sulphur  employed  one  pound  of  water 
should  be  vaporized.  It  is  germicidal  in  from  6  to  24  hours. 
For  the  destruction  of  insects  2  pounds  of  sulphur  per  1000 
cubic  feet  are  sufficient.  It  should  act  from  2  to  12  hours 
when  used  for  this  purpose. 


Pig.  9. — For  purpose  of  fumigation  all  cracks  around  doors  and  windows  except 
the  door  of  exit  should  be  sealed  with  adhesive  paper. 

Sulphur  dioxid  is  most  commonly  and  conveniently  generated 
by  the  burning  of  sulphur.  Ordinary  stick  sulphur  is  crushed 
to  fineness  and  the  required  amount  is  placed  in  a  conical  pile  in 
a  shallow  cast  iron  pot  or  jar,  which  is  supported  on  bricks 
in  a  tub  containing  1  to  2  inches  of  water  (Fig.  8).     A  small 


102 


PRACTICAL    PREVENTIVE    MEDICINE 


conical  depression  is  made  in  the  top  of  the  pile  and  in  this  is 
placed  a  small  ball  of  waste  saturated  with  alcohol.  The 
alcohol  is  ignited  and  its  burning  is  sufficient  to  ignite  the  sul- 
phur.    It  is  important  that  the  pots  employed  be  shallow. 

{c)  Preparation    oj    Quarters   jor    Fumigation. — All    cracks 
around  doors  and  windows  except  the  door  of  exit  should  be 


Manilla  paper 


ROPE ON  INNER  side 


OF  PAPER. 


Fig. 


^s   UNITED  STATES  PUBLIC  HEALTH  SERVICE 

■Rope  to  ground 


io. — Detail  of  preparation  of  window  for  rapid  ventilation  after  fumigation. 
{From  Trask:  Suppl.  15,  P.  H.  Rep.) 


sealed  with  adhesive  paper,  but  the  lower  windows  should  not 
be  locked  (Fig.  9).  Open  all  closet  doors  and  bureau  drawers. 
When  the  mixture  of  the  reagents  is  set  off,  immediately  leave 
by  the  unsealed  door  and  seal  this  from  the  exterior.  When  the 
required  period  of  exposure  is  completed ,  the  ground  floor  win- 
dows can  be  opened  from  the  outside  and  ventilation  estab- 
lished.    The  quarters  should  be  thoroughly  aired  before  they 


DISINFECTANTS    AND    DISINFECTION  103 

are  entered.  When  an  entire  home  or  building  is  to  be  fumi- 
gated, ventilation  after  the  completion  of  fumigation  will  be 
facilitated  by  the  sealing  of  the  upper  story  windows  in  the 
manner  illustrated  in  Fig.  10,  by  which  means  they  can  be 
opened  from  the  ground. 

9.  Insecticides. — The    employment    of    these    will    be    con- 
sidered later. 

REFERENCES 

Rosenau:  Preventive  Medicine   and  Hygiene.     3rd   ed.   pp.    1099-1176. 

Practical  Use  of  Disinfectants.     Reprint  286,  Public  Health  Reports. 

Report    on    an    Original   Form  of  Sulphur  Burner  for  Disinfection.     Reprint 

59,  Public  Health  Reports. 
Disinfectants:  their   use   and  application  in  the  prevention  of  communicable 

diseases.     Public  Health  Bulletin  42,  U.  S.  P.  H.  S. 
The  limitations   of   formaldehyde  gas   as   a  disinfectant.     Bulletin   27,   Hyg. 

Lab.,  U.  S.  P.  H.  S. 
Some    common    disinfectants.     Farmer's   Bulletin  926,   U.   S.   Department  of 

Agriculture. 
Anderson  and  McClintic:   Hyg.   Lab.  Bulletin  82,  U.  S.  P.  H.  and  M.  H. 

Service. 


CHAPTER  XIII 
EXCRETA  DISPOSAL 

The  term  excreta  is  a  collective  one,  applied  to  both  human 
feces  and  urine.  These  discharges  have  a  direct  relationship 
to  health  for  the  following  reasons: 

(a)  Several  different  species  of  infective  agents  leave  the 
body  by  this  means,  from  which  they  may  be  transmitted  to 
other  persons  by  the  agencies  of  contact,  contamination  of 
water  supplies  with  excreta,  and  by  the  contamination  of  house 
flies  with  excreta. 

(b)  In  addition,  lack  of  care  in  the  collection  and  removal 
of  these  discharges  will  give  rise  to  collections  of  decomposing 
organic  matter  about  habitations,  which  are  exceedingly  offen- 
sive to  the  senses.  In  other  words,  it  then  constitutes  a 
nuisance. 

i.  Modern  Urban  Methods  of  Excreta  Disposal. — The  neces- 
sity for  these  methods  has  arisen  from  the  extreme  congestion 
of  urban  population  which  characterizes  the  present  era.  Ur- 
ban sewer  systems  were  originally  devised  for  the  removal  of 
storm  and  ground  water,  not  for  the  removal  of  excreta.  Thus 
not  until  1815  was  fecal  matter  permitted  in  the  London  sewers, 
in  1833  in  Boston  and  in  1880  in  Paris.  Water  closets  as  we 
know  them,  date  from  the  report  of  tne  English  Health  of 
Town's  Commission  in  1844  and  were  not  connected  with 
sewers  until  1847.  The  successful  employment  of  water  closets 
requires  that  an  abundant  supply  of  water  under  pressure  be 
available,  inasmuch  as  the  solid  fecal  debris  is  transported  in  the 
sewers,  particularly  the  house  drains  and  lateral  sewers,  by  the 
velocity  of  the  water  current.  Hence  the  present  system  of 
excreta  removal  widely  employed  in  our  cities  and  towns  is 
known  as  the  water  carriage  system. 

2.  Sewerage. — Sewerage  is  the  term  applied  to  the  under- 
ground system  of  drains  by  which  excreta  is  removed  inoffen- 
sively. While  the  development  of  such  systems  has  relieved 
a  certain  set  of  sanitary  problems  by  removing  these  offensive 
accumulations  from  around  urban  dwellings,  yet  the  transporta- 
tion of  the  excrement  of  an  entire  city  without  its  bounds,  and 

104 


EXCRETA   DISPOSAL  105 

its  concentration  at  one  or  a  few  points  has  given  rise  to  an 
entirely  new  set  of  problems,  which  we  shall  consider  later. 

In  a  consideration  of  a  sewerage  system  certain  terms  are 
used,  which  we  will  define  here: 

(a)  A  combined  sewerage  system  is  one  that  receives  both 
domestic  sewage  as  well  as  the  surface  wash  of  the  streets, 
known  as  storm  water. 

(b)  Sanitary  sewers  are  those  that  receive  domestic  sewage 
alone. 

(c)  Storm  sewers  are  those  that  receive  storm  water  or  street 
washings  alone. 

The  last  two  systems  are  the  best  where  methods  of  sewage 
treatment  are  employed,  inasmuch  as  the  large  volumes  of 
storm  water  interfere  seriously  with  the  operation  of  the  sewage 
disposal  plants. 

A  sewerage  system  consists  of  the  following  components, 
the  names  of  which  are  self  explanatory.  Starting  at  the  dwell- 
ings we  have  the  house  drains,  which  discharge  into  the  lateral 
sewers,  which  in  turn  discharge  into  the  trunk  sewers,  which 
carry  the  excreta  to  the  point  of  disposal.  Trunk  sewers  may 
be  connected  to  intersecting  sewers  which  carry  the  excreta 
still  further  away. 

3.  Sewage. — Sewage  is  the  material  which  flows  through  the 
sewers.  It  consists  of  the  waste  water  supply,  plus  ground 
water  leakage  into  the  sewers  plus  domestic  water  wastes,  plus 
excreta,  plus  industrial  wastes  and  perhaps  storm  water  in 
addition.  In  dry  weather  its  volume  approximates  the  daily 
water  consumption  of  the  community.  Per  capita  its  daily 
volume  in  small  towns  will  be  from  40  to  50  gallons,  in  large 
cities  from  100  to  200  gallons.  Per  capita  its  average  composi- 
tion will  be  about  the  following: 

Average  daily  water  consumption 285,000  gms. 

Fecal  solids 100  gms. 

Urinary  solids 50  gms. 

Miscellaneous  solids 500  gms. 

From  the  standpoint  of  its  composition  we  may  consider 
sewage  to  be  a  more  or  less  homogenous  suspension  of  fine 
particles  with  organic  and  mineral  matter  in  solution.  The 
organic  matter  present  is  very  unstable  so  that  its  chemical 
composition  is  variable,  depending  on  the  age  of  the  material. 
Important  organic  constituents  are  urea,  albumen,  fibrin,  casein, 


io6 


PRACTICAL    PREVENTIVE    MEDICINE 


starch,   sugar,  fats,  and  soaps.     Of  the  elemental  substances 
present  nitrogen  and  sulphur  are  of  the  greatest  importance. 

4.  Sewage  Disposal  by  Dilution.— The  large  volume  of  water 
present  demands  that  economical  transportation  be  effected 
by  gravity,  and  that  it  be  discharged  into  some  convenient 
water  course.     The  discharge  of  the  untreated  sewage  into  some 


Fig.  11. — Diagram  illustrating  self-purification  in  the  Thames,  England. 
The  discharge  of  the  large  volume  of  sewage  from  London  soon  markedly  lowers 
the  dissolved  oxygen,  which  however  is  restored  by  the  time  the  water  reaches 
the  river's  estuary.      (U.  S.  Geological  Survey,  W.  S.  Paper  185.) 

water  course  is  known  as  disposal  by  dilution.  It  has  given 
rise  to  a  series  of  problems,  arising  from  nuisances  and  the 
contamination  of  public  water  supplies,  from  which  have 
developed  the  modern  methods  of  sewage  treatment  and  water 
purification. 

If  the  body  of  water  into  which  the  raw  sewage  is  discharged 
is  of  sufficient  volume,  disposal  by  dilution  may  be  sufficient. 


EXCRETA   DISPOSAL  107. 

On  the  other  hand,  if  the  diluting  body  is  of  insufficient  volume, 
or  if  drinking  water  supplies  are  contaminated,  or  oyster  beds 
are  contaminated,  or  a  nuisance  is  produced,  it  is  unsatisfac- 
tory or  even  dangerous. 

When  the  process  is  satisfactory  the  following  events  take 
place: 

(a)  There  is  a  sedimentation  of  the  heavy  particles. 

(b)  There  is  an  oxidation  of  the  organic  matter  into  stable  and 
inoffensive  substances  by  bacterial  activity  through  the  dis- 
solved oxygen  in  the  water  (Fig.  n). 

(c)  There  is  a  gradual  destruction  of  the  fecal  bacteria  due 
to  their  introduction  into  an  unfavorable  environment  and  the 
activity  of  predatory  protozoa. 

Where  a  stream  receives  sewage  we  rind  that  for  a  distance 
of  several  miles  below  the  sewer  outfalls,  definite  evidence  of 
the  sewage  contamination  is  observable,  but  that  at  a  greater 
distance  the  stream  bed  and  1he  water  assume  an  appearance 
similar  to  that  above  the  entrance  of  the  sewage  and  its  ap- 
pearance is  no  longer  offensive.  This  phenomenon,  due  to 
the  above  agencies,  is  known  as  the  "self  purification"  of 
streams. 

Where  dilution  is  insufficient  we  find  that  the  sedimented 
material  and  dissolved  matter  does  not  undergo  oxidation,  but, 
due  to  insufficient  oxygen,  undergoes  anaerobic  decomposition 
with  the  production  of  offensive  gases  and  odors;  that  the  dis- 
solved oxygen  is  consumed  and  fish  life  cannot  survive. 

Factors  which  limit  the  successful  operation  of  this  method 
of  disposal  are  the  following: 

(a)  The  sewage  should  not  greatly  exceed  i  per  cent,  of  the 
volume  of  the  water  into  which  it  is  discharged,  though  this 
factor  varies  directly  with  the  rapidity  of  the  stream,  since  re- 
oxygenation  is  more  speedy  in  rapid  streams. 

(b)  The  amount  of  dissolved  oxygen  in  the  water,  which  is 
greater  during  cold  periods  than  in  warm  weather.  It  must  be 
remembered  that  the  capacity  of  salt  water  for  dissolved  oxy- 
gen is  about  20  per  cent,  less  than  fresh  water. 

(c)  The  rate  of  the  dispersion  of  the  sewage  in  the  diluent. 
This  must  be  quick. 

5.  Sewage  Treatment. — When  satisfactory  disposal  by  dilu- 
tion cannot  be  secured,  the  treatment  of  the  sewage  is  necessary. 
The  following  results  are  sought: 

(a)  A  separation  of  the  suspended  matters  (sludge)  from  the 
liquid  sewage. 


io8 


PRACTICAL    PREVENTIVE    MEDICINE 


{b)  The  destruction  of  the  putrescible  organic  matter  in  the 
liquid  sewage  preparatory  to  its  final  mineralization  by  oxida- 
tion (non-putrescibility). 

(c)  The  transformation  of  the  sludge  into  a  stable  and  inert 
condition,  with  or  without  the  aid  of  oxidation. 

(d)  The  destruction  or  removal  of  bacteria  from  the  effluent. 
Several  methods  are  employed  to  secure  the  above  results 

which  are  used  either  singlv  or  in  various  combinations.  Great 
care  and  judgement  must  be  employed  in  selecting  the  method 
of  treatment  to  be  employed,  since  different  methods  of  treat- 


Fig.  12. — Fine  mesh  revolving  screen  at  Birmingham,  England.  (Courtesy 
of  J.  D.  Watson.)  These  screens  constantly  revolve  so  that  a  fresh  surface  is 
always  ready  for  use.      (Am.  Mus.  Nat.  Hist.,  Guide  Leaflet,  33.) 

ment  vary  in  the  degree  of  their  successfulness,  depending  upon 
the  character  and  composition  of  the  sewage  to  be  treated,  as 
well  as  the  degree  of  attention  paid  to  the  care  of  the  disposal 
plants.  All  sewage  treatment  plants  require  intelligent  opera- 
tion, together  with  some  degree  of  skill.  Most  dissatisfaction 
or  failure  can  be  traced  to  either  neglect  or  ignorant  operation. 
Sewage  treatment  plants  should  be  designed  by  competent 
sanitary  engineers,  after  study  and  experimentation  has  re- 
vealed the  method  of  treatment  best  suited  to  handle  the 
local  sewage. 


EXCRETA   DISPOSAL 


109 


6.  Preparatory  Processes. — These  are  designed  to  effect  a 
separation  of  the  suspended  matter  or  sludge  from  the  liquid 
sewage. 

(a)  Screening. — Coarse  or  fine  gratings  or  screens  are  placed 
across  the  path  of  the  sewage  to  remove  coarse  material,  which 
is  removed  from  the  screens  at  frequent  intervals  and  either 
buried  or  burned  (Fig.  12). 

(b)  Sedimentation. — Most  of  the  suspended  matter  is  removed 
by  sedimentation.  The  velocity  of  the  stream  of  sewage  is 
lowered  and  as  a  consequence  the  fine  suspended  particles 
settle.  Various  means  are  employed  to  apply  this  principle. 
Among  them  are  the  following: 

1.  Grit  Chambers. — These  are  small  chambers,  in  which  the 
velocity  of  the  sewage  is  but  slightly  reduced,  so  that  only  the 


Pig.  13. — Septic  tank  or  modified  sedimentation  basin.     Photograph  of  a 
model  in  the  American  Museum.      (Am.  Mus.  Nat.  Hist.,  Guide  Leaflet  33.) 


heavier  of  the  suspended  particles  settle  out.  Because  of  their 
size  the  period  of  sedimentation  is  brief.  They  are  chiefly 
used  to  effect  a  removal  of  sand  and  gravel  in  combined  sewerage 
systems.     These  chambers  must  be  cleaned  frequently. 

2.  Plain  Settling  Tanks. — These  are  large  basins  in  which  the 
sewage  is  retained  from  one  to  twelve  hours.  The  sludge  is 
removed  frequently  and  is  not  permitted  to  undergo  decomposi- 
tion in  the  tank  (Fig.  13). 

3.  Septic  Tanks. — In  construction  these  tanks  are  similar  to 
the  foregoing  and  differ  only  in  the  method  of  their  operation. 
The  low  velocity  of  the  sewage  in  passing  through  the  tank 
results  in  its  detention  for  8  to  24  hours,  so  that  practically 
all  of  the  suspended  matter  is  deposited.     This  is  permitted 


no 


PRACTICAL   PREVENTIVE    MEDICINE 


to  accumulate  at  the  bottom  of  the  tank  for  long  periods,  where, 
in  the  absence  of  free  oxygen,  it  undergoes  anaerobic  decomposi- 
tion. As  a  result  of  the  decomposition  the  volume  of  the 
sludge  is  very  much  reduced.  Bubbles  of  gas  from  the  decom- 
position changes  in  the  sludge,  may  bring  extensive  masses  of 
sludge  to  the  surface  where  it  floats  as  a  scum  several  feet  thick. 
Removal  of  the  sludge  is  generally  only  undertaken  when  such 
a  volume  has  accumulated  so  as  to  seriously  reduce  the  capacity 
of  the  tank  (Fig.  14). 


FlG.  14. — Septic  tanks,  Columbus,  Ohio.  Twenty  million  gallons  of  sewage  a 
day  can  be  treated  in  this  recently  constructed  plant.  (Am.  Mus.  Nat.  Hist., 
Guide  Leaflet  33.) 


4.  Two  Story  Digestion  Tanks. — Several  different  designs  of 
digestion  tanks  belong  to  this  group,  of  which  the  best  known 
are  the  Imhoff  tanks.  From  their  construction  the  sludge  is 
permitted  to  settle  in  a  lower  chamber,  where  it  undergoes 
anaerobic  decomposition  out  of  contact  with  the  fresh  flowing 
sewage.  As  a  consequence  the  effluent  of  these  tanks  is  less 
offensive,  and  the  digestion  of  the  sludge  in  the  lower  chamber 
is  more  complete  (Figs.  15,  16). 

5.  Chemical  Precipitation. — This  method  is  of  very  limited 
application  and  its  use  is  practically  limited  to  those  communi- 
ties where  iron  wastes  in  the  sewage  render  the  accomplish- 


EXCRETA   DISPOSAL 


III 


ment  of  a  precipitating  reaction  easy.  The  floculi  thus  formed 
enmesh  the  fine  suspended  particles  and  hasten  their  removal. 
After  the  reaction  of  precipitation  has  occured,  the  sewage  is 


Inlet  Channel 


Outlet  Weirs 


Plan 
Fig.   15. — A  digestion  tank  of  the  Imhoff  type.     Section  C-C  is  a  longitudinal 
view  and  Section  D-D  is  a  transverse  view.      (After  Gregory:  Engineering  Record, 
I9I5.) 


Fig.   16. — Twin    Imhoff    settling    tanks    at    Chambersburg    Sewage-Treatment 
Plant.      (Mebus,  Engineering  Record,  1914.) 

run  into  large  open  tanks  for  sedimentation  to  take  place. 
Precipitation  is  accomplished  by  the  employment  of  lime,  fer- 
rous sulphate  or  alum.     The  principles  are  similar  to  the  em- 


112 


PRACTICAL   PREVENTIVE    MEDICINE 


ployment  of  coagulants  in  water  purification  which  will  be 
spoken  of  later  in  more  detail. 

6.  Activation. — In  the  sedimentation  chambers  previously 
described,  the  decomposition  of  the  sludge  is  anaerobic  in 
character,  offensive  gases  are  produced  and  the  stable  sludge 
finally  produced  has  little  value.  In  the  activation  process, 
compressed  air  is  admitted  to  the  tanks  through  porous  plates 
in  the  bottom,  and  as  a  consequence  aerobic  processes  of  decom- 
position are  facilitated.  The  sludge  is  rapidly  oxidized,  is  non- 
offensive  and  has  considerable  value  as  a  fertilizer  (Fig.  17). 


Fig.   17. — Air-diffusers  in  sloping  bottom  of  activated  sludge  tank. 
{Engineering  Record,  191 5.) 


7.  Roughing  Filters. — These  are  large  vats  or  tanks  filled  with 
coke,  crushed  stone,  or  similar  material,  and  filled  with  sewage. 
As  a  consequence  of  the  rock  or  other  inert  material  present, 
sedimentation  is  facilitated,  since  the  vertical  distance  a  sus- 
pended particle  has  to  pass  to  reach  a  firm  support  is  very 
much  reduced. 

7.  Sludge  Disposal. — The  amount  of  suspended  matter 
collected  in  the  tanks  is  considerable  and  since  (except  in  that 
collected  in  the  activation  process),  its  value  is  slight  or  nothing, 
the  disposal  of  sludge  is  usually  considerable  of  a  task  and  a 
problem.  Digestion  measures  considerably  reduce  the  volume 
to  be  disposed  of,  but  do  not  altogether  dispose  of  the  sludge. 
The  following  additional  measures  are  employed: 

(a)  Pressing  the  sludge  in  filter  presses  to  remove  the  surplus 


EXCRETA   DISPOSAL  113 

moisture.     This  is  necessary   to  permit  its   ready  handling. 

After  a  drier  sludge  is  secured  it  is  either : 
(b)  Used  for  filling  low  areas  of  land,  or 
(c).  Loaded  onto  cars,  or  barges  and  dumped  at  sea. 
(d)  Some   of   the  more   stable   sludges,   for   example   those 

secured  from  the  Imhoff  tanks,  are  run  off  into  drying  beds. 

When  dry  the  sludge  is  of  loamy  consistency  and  is  then  scraped 

off  and  buried  in  trenches. 


CHAPTER  XIV 

EXCRETA  DISPOSAL  (CONTINUED) 

8.  Purification  Processes. — These  processes  are  designed  to 
treat  the  effluent  from  the  various  types  of  sedimentation  basins 
to  secure  a  stable  effluent,  that  is,  one  which  is  not  subject  to 
further  decomposition  changes.  Where  satisfactory  most  of 
the  nitrogen  will  have  been  changed  to  nitrates.  All  depend 
upon  active  oxidation,  which  is  secured  by  microbial  activities. 
The  following  methods  are  employed  to  secure  this  result : 


Fig. 


18. — Intermittent  sand  filter  bed.     Photograph  of  a  model  in  the  American 
Museum.     (Am.  Mus.  Nat.  Hist.  Guide  Leaflet 33.) 


{a)  Subsurjace  Irrigation. — The  effluent  is  intermittently  dis- 
charged through  one  or  more  strings  of  open  joint  tile  just  under 
the  surface  of  the  ground.  The  liquid  is  thus  discharged  into 
the  layer  of  soil  where  bacterial  activities  are  greatest.  The 
method  is  only  adapted  to  open  or  porous  soils,  particularly 
under  rural  conditions  where  the  volume  of  liquid  is  small. 
(Figs.  26  and  27).  The  soil  must  not  be  permitted  to  become 
water  logged,  otherwise  aerobic  decomposition  will  be  super- 
seded by  anaerobic,  and  a  nuisance  result. 

1141 


EXCRETA   DISPOSAL 


"5 


(b)  Broad  Irrigation. — The  sewage  effluent  is  discharged 
into  irrigation  furrows  on  cultivated  land  and  permitted  to 
percolate  downward  through  the  soil.  This  method  is  only 
adapted  to  open  or  porous  soils,  preferably  in  arid  regions, 
where  water  for  purposes  of  irrigation  is  at  a  premium.  Under 
these  circumstances  it  may  pay  for  itself.  It  has  not  been  a 
success  in  this  country. 

(c)  Intermittent  Sand  Filtration. — The  effluent  is  applied  in- 
termittently, soaks  quickly  away  and  most  of  the  time  the 
filter  is  exposed  to  the  air.  With  proper  operation  very  good 
results  are  secured.  On  the  other  hand,  if  too  large  quantities 
of  effluent  are  applied,  or  applied  too  frequently,  the  filter  be- 
comes water  logged  and   oxidation  is  prevented.     Its  use  is, 


Fig.   19. — Double  contact  beds  for  purification  of  sewage.     Photograph  of  a 
model  in  the  American  Museum.      {Am.  Mus.  Nat.  Hist.  Guide  Leaflet  33.) 

practically  limited   to  areas  of  sandy  soil.     These  should,  be 
ridged  for  winter  operation  to  prevent  freezing  (Fig.  18). 

(d)  Contact  Beds. — These  are  similar  in  construction  to 
roughing  niters,  but  are  operated  int  ermittently  on  the  fill  and 
draw  method.  The  suspended  matter  settles  on  the  crushed 
stone.  When  the  tanks  or  beds  are  full  the  action  is  septic  or 
anaerobic,  when  empty  the  matter  on  the  stone  is  subjected 
to  aerobic  or  oxidative  action.  The  beds  are  usually  operated 
in  series  (Fig.  19). 

(e)  Trickling  Filters. — These  are  concrete  vats,  on  the  floor 
of  which  are  open  tile  drains,  and  above  which  are  several  feet 
of  crushed  rock,  over  which  the  sewage  effluent  is  sprinkled  or 
sprayed.  The  interstices  of  the  rock  are  exposed  to  the  air 
at  all  times  when  properly  operated.     As  a  consequence  com- 


n6 


PRACTICAL   PREVENTIVE   MEDICINE 


plete  aeration  is  secured  and  the  effluent  is  stable.  They  are 
well  adapted  to  areas  where  sandy  soil  is  not  available  (Fig.  20). 
9.  Finishing  Processes. — In  the  first  three  methods  de- 
scribed above,  the  filtered  effluent  joins  the  ground  water.  In 
the  latter  two  it  is  discharged  from  the  beds  into  some  water 
course.  In  order  to  destroy  any  pathogenic  bacteria  which 
have  managed  to  pass  through  the  treatment  beds,  the  present 
practice  is  to  sterilize  the  effluent  by  the  employment  of 
chlorine,  either  as  compressed  chlorine  or  bleach.  The  methods 
of  application  are  similar  to  those  used  in  water  disinfection 

r    •  w  "  ~""~~      ^^^    :  -— 


lAhUhllii    lit    ili  1  if    •'  — '-^fj  ■■■' -*-f--M-rTT" 


as 


ww  ww  w^'^rw'^fytt 


Pig.  20. — Trickling  filters,  Columbus,  Ohio.  By  means  of  fixed  sprinkler 
nozzles,  sewage  is  sprayed  evenly  over  the  surface  of  a  bed  of  coarse  stone. 
This  method  is  at  present  considered  one  of  the  most  effective  of  all  devices  for 
sewage  purification.     {Am.  Mus.  Nat.  Hist.  Guide  Leaflet  33.) 

where  they  will  be  discussed  in  more  detail.  The  quantity 
applied  varies  with  the  condition  of  the  effluent.  It  is  also 
applied  to  raw  or  unsettled  sewage  where  other  treatment  is 
not  used. 

10.  Domestic  Excreta  Disposal. — We  will  now  consider  the 
methods  of  excreta  disposal  available  for  isolated  dwellings, 
for  example  those  in  unsewered  portions  of  cities  and  towns, 
unsewered  villages,  farm  homes,  summer  resorts,  and  camps. 

It  is  essential  that  individuals  under  these  circumstances  be 
sufficiently  educated  in  personal  hygiene  to  realize  the  impor- 
tance (1)  of  having  som-?  place  about  the  dwelling  where  the 


EXCRETA  DISPOSAL 


117 


excreta  of  all  members  of  the  household  is  concentrated,  (2) 
that  at  the  place  of  concentration  the  excreta  is  so  cared  for 
that  it  is  not  a  further  menace  to  their  health,  and  (3)  that 
modesty,  decency,  and  cleanliness,  are  cultivated.  Only  where 
these  are  observed  can  soil  pollution  or  contamination  by  ex- 
creta be  prevented  (Figs.  21,  22),  and  domestic  water  supplies 
be  safeguarded. 

The  methods  suitable  to  any  given  home  will  depend  whether 
or  not  domestic  water  pressure   is  available.     In  the  absence 


LH  yiicoEf^. 


Pig.   21. — An  unsanitary  privy  of  primitive  type  permitting  extensive  soil  pollu- 
tion.     Drawn  from  a  photograph.      (P.  H.  Bull.  68.      U.  S.  P.  H.  S.) 


of  domestic  water  pressure  either  of  the  two  following  methods 
may  be  employed: 

(a)  The  So-called  Chemical  Closets. — These  are  simple  in- 
stallations for  the  interior  of  the  dwelling,  in  which  the  excreta 
is  received  into  a  strong  caustic  solution,  which  disinfects  the 
material.  If  properly  cared  for  they  will  probably  give  satis- 
factory results  (Fig.  23). 

(b)  Privies. — A  satisfactory  privy  should  protect  the  excreta 
from  flies,  rats,  hens,  pigs,  etc.,  and  should  be  well  ventilated 
to  permit  the  ready  evaporation  of  the  liquid  excreta.     Their 


II< 


PRACTICAL   PREVENTIVE    MEDICINE 


Fig.  22. — Typically  unsanitary  privy  at  a  farm  home,  showing  flies  swarming 
about  the  privy  contents.  The  excreta  are  deposited  upon  the  surface  of  the 
ground.      (Lumsden:  P.  H.  Bull.  94.      U.  S.  P.  H.  S.) 


AWl  M/CXC17  00V  fVAM 

W 


Pig.   23. — Sketch  showing  general  arrangement  of  a  chemical  closet.      (Cour- 
tesy of  the  Dail  Steel  Products  Company.)      (Hansen:   Illinois  Health  News.) 


EXCRETA    DISPOSAL 


119 


successful  operation  depends  upon  the  degree  of  simplicity  in 
their  construction,  as  a  general  proposition  those  whose  success- 
ful operation  requires  continuous  care  are  neglected  sooner  or 
later.  All  should  be  well  screened  and  have  a  tight  seat  cover. 
Privies  are  usually  of  the  following  types: 

1.  Vaulted. — The  excreta  are  deposited  into  a  pit  or  vault 
underneath.  The  pit  should  be  made  water  tight  by  means  of 
concrete  walls  and  bottom  (Fig.  24). 

2.  Pail  or  Can  Privies. — The  excreta  are  deposited  in  large  pails 
or  buckets  fitted  underneath  the  seat.  At  voiding  the  person 
using  the  privy  may  cover  the  excreta  with  a  thin  layer  of  dry 
earth  or  ashes.     Thev  require  constant  attention,  are  apt  to  be 


Fig.   24. — A  stationary-receptacle  sanitary  privy-  with  a  cement  vault  arranged 
for  convenient  clearing.      (P.  H.  Bull.  68,  U.  S.  P.  H.  S.) 

neglected  and  hence,  if  privately  controlled,  are  troublesome 
(Fig.  25).  The  wide  spread  employment  of  this  type  of  privy-  in 
unsewered  towns,  or  unsewered  areas  of  towns,  should  be  under 
municipal  supervision.  Provision  should  be  made  for  the  ex- 
change of  receptacles  at  frequent,  regular  intervals,  if  satisfac- 
tory results  are  to  be  secured.  The  expense  of  maintainence  of 
such  a  system  is  high,  which  tends  to  stimulate  a  desire  for  the 
early  installation  of  a  sewerage  system.  The  excreta  (or  night 
soil)  are  disposed  of  either  by  burial  or  incineration. 

3.  Leaching  Privies. — These  are  apt  to  be  unsatisfactory  or 
dangerous.  No  pit  is  provided  and  the  excreta  are  deposited  on 
the  surface  of  the  ground.     They  should  be  located  with  care 


120 


PRACTICAL    PREVENTIVE    MEDICINE 


with  particular  reference  to  surface  drainage  and  are  not  suit- 
able for  clay,  gravely  soil  or  limestone  soils.  They  are  not  to 
be  recommended. 


When   domestic   water   pressure  is  available  cess-pools  are 
commonly  employed.     The  closet  is  located  within  the  house 


EXCRETA    DISPOSAL 


121 


h 


,Siudge  Outlet 


Sludge    Outh 


Sub-Surfoce  Drain' 


SUGGESTIVE   DESIGN 

FOE« 

SEWAGE  TANK  WITH  DOSING  GHAMBEB 
DISCHARGING  INTO   A  DBAIN  TILE 
SUB-SUPFflCE  DISPOSAL  SYSTEM 

SCALE         in      FEET 


Pig.  26. — Simple  form  of  tank  built  in  conjunction  with  a  dosing  chamber 
for  applying  the  sewage  in  doses  on  secondary  treatment  devices,  suitable  for 
domestic  installation.      See  Pig.  27.      (After  Hansen:  Illinois  Health  News.) 


Pig.  27. — Typical  plan  for  a  subsurface  sewage  disposal  system  for  domestic 
installation.      (After  Hansen:   Illinois  Health  News.) 


122 


PRACTICAL  PREVENTIVE  MEDICINE 


and  water  carriage  is  employed  to  transport  the  excreta  to  the 
point  of  disposal.     These  are  of  two  main  types: 

(a)  Vaulted  Cesspools. — These  have  concrete  bottoms,  sides 
and  top,  and  are  in  reality  septic  tanks.  The  sludge  should 
be  burned,  buried,  or  disinfected,  while  the  effluent  is  best  dis- 
posed of  by  subsurface  irrigation  (Figs.  26,  27). 


Roricultural  drain 
tile  pipe 


\y5Mpsof  far  paper 
V  laid  aw  tops  of  joints 


Hollow  brick 
/aid  radially 


^Manhole  frame  and  cover 


/-?/  /  /  A 

1  o-a  |  a  □ 

□  □ 

a  d  IAi 

/lap 

DD 

a°l//J 

|aa|  ao 

an 

□  □  |/ 

|QD 

dd 

aaj/ 

De+aita  of  Hollow  Bric/% 

Pig.   28. — Hollow  brick  cesspool  of  the  leaching  type  with  overflow  into  agri- 
cultural tile.      (Horton:  N.  Y.  State  Dep't.  Health.) 

(b)  Leaching  Cesspools. — These  do  not  have  either  a  light 
bottom  or  walls.  The  liquid  contents  escape  into  the  soil 
below  the  zone  of  active  oxidation  and  hence  may  contaminate 
the  ground  water  for  some  distance.  They  should  not  be  used 
in  clay  or  gravely  soils  or  in  limestone  regions  (Fig.  28). 


REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene,  3rd  Ed.,  Sewage  Disposal,  by 

George  C.  Whipple,  Sec.  VII,  pp.  955-979. 
Daniels:  The  Operation  of  Sewage  Disposal  Plants. 
Lumsden:  A  Sanitary   Privy   System   for   Unsewered    Towns  and   Villages. 

Public  Health  Bulletin  No.  89.     U.  S.  P.  H.  S. 


EXCRETA    DISPOSAL 


123 


Hansen:  Disposal  of  Sewage  from  Country  Homes,  Small  Institutions  and 

Country  Clubs.     Illinois  Health  News.     Aug.,  1916.     Published  by  111. 

State  Board  of  Health. 
Horton:  The  disposal  of  human  excreta  and  sewage  of  the  country  home. 

New  York  State  Department  of  Health. 
Faber:  The   operation    and   care  of   sewage   disposal   plants.     Bulletin    16. 

Engineering  Extension  Department.     Iowa  State  College,  Ames. 
The   treatment    of    sewage    from    single    houses    and   small    communities. 

Reprint  506,  Public  Health  Reports. 
Chemical  closets.     Reprint  404,  Public  Health  Reports. 
See  also  various  water  supply  papers  of  the  U.  S.  Geological  Survey. 


CHAPTER  XV 

THE  RELATIONSHIP  OF  WATER  TO 
HEALTH  AND  DISEASE 

While  water  is  not  technically  a  food,  it  is  an  essential  article 
of  the  diet.  In  addition  it  bears  an  important  relationship  to 
personal  hygiene,  inasmuch  as  it  is  essential  in  the  maintenance 
of  proper  cleanliness  of  the  person,  the  clothing  and  other 
objects. 

1.  Relationship  to  Health  and  Disease. — The  body  requires 
an  adequate  daily  supply  for  its  physiologic  uses.  The  amount 
required  by  the  male  adult  represents  the  maximum  consump- 
tion for  this  purpose,  varying  from  1800  to  2100  c.c.  of  water 
ingested  as  such,  with  approximately  600  c.c.  additional  ingested 
with  the  solid  food. 

Water  bears  an  important  relationship  to  the  communicable 
diseases,  as  it  may  be  an  important  route  in  the  transmission 
of  several  species  of  infective  agents.  The  properties  which 
make  it  important  in  this  connection  are  the  following: 

(a)  It  is  ordinarily  consumed  raw,  i.e.,  it  has  not  been  heated 
or  otherwise  subjected  to  any  treatment  that  will  destroy  any 
infective  agents  present. 

(b)  In  its  normal  cycle  of  circulation  it  comes  in  contact  with 
a  great  variety  of  material  spread  over  vast  areas,  hence  if  ex- 
creta be  present  in  the  open,  they  will  be  transported,  together 
with  infective  agents  present,  by  the  water.  Furthermore  m  any 
natural  sources  of  water  supply  are  frequently  contaminated, 
very  often  grossly  so,  by  the  direct  discharge  of  sewage. 

Water  also  serves  as  a  solvent  for  certain  inorganic  poisons. 

2.  Conditions  which  Favor  the  Contamination  of  Water  and 
the  Transfer  of  Infective  Agents. — Of  the  relationship  of  water 
to  disease,  that  in  connection  with  the  transfer  of  infective 
agents  is  of  greatest  importance.  The  following  conditions 
render  the  employment  of  a  contaminated  and  infected  water 
possible  and  probable: 

(a)  The  use  of  water  which  receives  the  sewage  of  other 
towns;  the  sewage  of  the  same  town,  the  sewage  of  individual 

124 


RELATIONSHIP    OF    WATER    TO    HEALTH   AND    DISEASE       1 25 

houses,  institutions  or  factories,  or  the  presence  of  privies  on  or 
over  a  stream. 

{b)  The  rush  of  floods  or  heavy  rains  which  transport  excreta 
deposited  on  the  surface  of  the  ground  into  a  water  course. 

(c)  The  use  of  double  supplies  coupled  together,  one  for  ordi- 
nary domestic  consumption,  the  other  from  an  unsafe  source 
for  emergency  fire  protection. 

(d)  Contamination  of  a  water  shed  from  labor  camps,  rail- 
road coaches,  or  excursionists. 

The  following  factors  influence  the  transfer  of  infective  agents 
by  water: 

(a)  The  quick  transfer  of  infective  agents  from  one  patient 
(source)  to  the  victim  in  the  person  of  the  consumer. 

(b)  The  probabilities  favor  the  short  survival  of  infective 
agents  in  water,  and  in  addition  their  multiplication  in  water  is 
doubtful. 

(c)  Cold  wa  ter  tends  to  prolong  the  period  of  their  survival. 
\d)  The  proportion  of  infective  excreta  to  the  volume  of  the 

diluting  water  is  usually  very  small,  so  the  dilution  of  the  micro- 
organisms is  enormous. 

(e)  Surface  water  supplies,  which  are  most  exposed  to  fecal 
contamination,  are  most  frequently  infected,  while  wells  and 
springs  are  less  often. 

The  foregoing  factors  have  given  water  borne  epidemics  cer- 
tain definite  characteristics  among  which  the  following  are  the 
most  conspicuous: 

(a)  Epidemics  occur  most  frequently,  and  endemic  water 
borne  typhoid  reaches  a  maximum  during  the  seasonal  periods 
(winter,  fall,  spring)  when  the  water  is  coldest. 

(b)  Water  borne  epidemics  have  an  abrupt  onset,  rise  rapidly 
to  a  maximum  and  rapidly  decline,  i.e.,  they  are  explosive. 

(c)  Investigation  usually  succeeds  in  revealing  a  nearby  con- 
tamination and  frequently  the  actual  source  or  sources  of  in- 
fection. 

(d)  Present  day  evidence  only  indicates  that  water  plays  a 
role  in  the  transmission  of  those  infective  agents  which  leave 
the  body  in  the  feces  and  urine,  for  example,  typhoid,  cholera, 
and  bacillary  dysentery. 

Indirectly  water  is  of  importance  as  a  breeding  place  for 
certain  insects,  such  as  mosquitoes,  concerned  in  the  transmis- 
sion of  other  infective  agents. 

3.  Inorganic  Poisoning  from  Water. — Lead  poisoning  from 
water  is  not  unknown.     Lead  is  not  found  in  natural  water, 


126  PRACTICAL   PREVENTIVE    MEDICINE 

and  when  present  is  derived  from  the  lead  service  pipes  or  some 
other  lead  object  connected  with  the  supply.  The  plumbo- 
solvent  power  of  water  depends  upon  the  following  factors: 

(a)  The  presence  of  a  free  acid,  such  as  carbonic  acid,  which 
is  found  in  soft  peaty  waters,  or, 

;  (b)  The  presence  of  an  excess  of  oxygen  and  little  dissolved 
matter,  such  as  soft  water,  or, 

(c)  The  presence  of  organic  matter,  nitrates  or  nitrites,  or 

(d)  The  presence  of  chlorides,  which  exert  a  solvent  power 
on  the  film  of  the  lead  carbonate  coating  the  pipe. 

The  following  conditions  also  affect  the  solvent  power  in 
direct  proportion:  the  duration  of  contact;  the  temperature; 
the  pressure;  and  the  purity  of  the  lead.  In  general  one  may 
say  that  turbid  and  hard  waters  have  the  least  plumbo-solvent 
power. 

In  the  new  England  States  lead  poisoning  from  this  source 
is  a  problem  to  be  constantly  borne  in  mind  and  is  usually 
overcome*  by  using  brass  pipes  instead  of  lead  pipes. 

4.  Source  of  Water  Supply. — Water  is  practically  derived 
from  three  sources : 

(a)  Rain  water,  which  is  the  ultimate  source  of  all  water. 
Practically  it  is  of  domestic  importance  only,  in  the  United 
States.  If  care  and  attention  are  directed  to  the  following 
points  a  satisfactory  supply  will  be  secured:  (1)  The  material 
and  care  of  the  collecting  surface;  (2)  Wastage  of  the  first  flow, 
and  (3)  Location  and  construction  of  the  storage  cistern. 

(b)  Surjace  water,  including  the  water  of  streams,  lakes,  and 
impounding  reservoirs.  Such  water  is  greatly  exposed  to  con- 
tamination and  its  dissolved  as  well  as  suspended  matter  is  very 
variable  in  amount.  Surface  water  is  widely  utilized  as  a  source 
for  municipal  supplies  because  of  the  vast  amount  available. 

(c)  Ground  water,  including  the  water  from  wells  and  springs. 
In  its  underground  passage  this  water  is  usually  subjected  to 
a  varying  degree  of  natural  filtration  and  is  less  subject  to 
contamination.  It  is  of  importance  as  both  a  domestic  and 
municipal  source  of  supply. 

5.  The  Hygienic  Examination  of  Water. — Valuable  informa- 
tion concerning  the  past  history  of  water  from  a  given  source 
of  supply,  and  hence  of  its  hygienic  value,  can  be  secured  by  a 
physical,  chemical  and  bacterial  examination.  Of  still  greater 
value  than  such  an  examination  however,  is  a  thorough  inspec- 
tion of  the  source  of  the  supply  by  one  competent  to  judge  pos- 
sible   sources    of    contamination.     Laboratory    examinations 


RELATIONSHIP    OF    WATER    TO    HEALTH    AND    DISEASE       I  27 

should  be  supplemental  to  such  surveys.  The  following  fea- 
tures are  usually  considered  in  a  laboratory  examination  of 
water  because  of  their  direct  or  indirect  bearing  upon  health: 

(a)  Odors. — These  are  in  themselves  harmless,  but  because 
of  their  offensive  character  result  in  complaints,  and  a  lessened 
consumption  of  water.  They  are  due  to  volatile  essential  oils 
liberated  from  the  bodies  of  microscopic  green  plants  (algae), 
and  are  usually  most  pronounced  in  stagnant  water  containing 
very  little  or  no  dissolved  oxygen. 

(b)  Taste  is  derived  from  matter  in  solution,  either  mineral 
or  gaseous.     It  may  render  a  supply  unpalatable. 

(c)  Color  is  of  vegetable  origin  and  is  due  to  material  in 
solution. 

(d)  Turbidity  is  due  to  material  in  suspension,  the  water  is 
said  to  be  muddy.  It  may,  if  excessive,  result  in  a  lessened 
consumption  of  the  water. 

(e)  Reaction. — The  reaction  of  water  is  normally  alkaline, 
due  to  the  carbonates  and  bicarbonates  of  calcium  and  mag- 
nesium in  solution.  Acid  waters  are  rare,  and  usually  owe  their 
acidity  to  either  trade  or  mine  wastes,  though  swamp  waters 
may  be  normally  acid. 

(/)  Total  Solids. — The  amount  of  dissolved  matter  in  water 
varies  widely.  Quantities  in  excess  of  500  parts  per  million 
are  commonly  considered  to  render  the  water  unfit  for  use. 

(g)  Hardness  is  either  temporary  or  permanent.  Temporary 
hardness  is  due  to  the  carbonates  or  bicarbonates  of  calcium 
or  magnesium,  while  permanent  hardness  is  due  to  the  chlorides 
or  sulphates  of  calcium  or  magnesium.  The  importance  of 
hardness  is  economic,  inasmuch  as  hard  waters  require  a 
much  greater  amount  of  soap  to  make  them  suitable  for  wash- 
ing purposes  than  do  soft  waters. 

(h)  Organic  matter  is  of  itself  of  doubtful  importance,  al- 
though some  outbreaks  of  diarrhea  have  been  ascribed  to  the 
presence  of  toxic  substances  of  putrefactive  origin.  Ordinarily 
the  chemical  examination  ascertains  the  scope  of  the  changes 
which  the  nitrogenous  compounds  have  undergone,  as  indicating 
something  of  the  changes  which  have  taken  place  in  dissolved 
organic  matter.  The  determination  of  nitrates  and  nitrites  is 
considered  of  greatest  importance.  The  nitrites  (N02)  sug- 
gest recent  organic  pollution,  though  if  present  in  small  quan- 
tities, their  significance  is  slight.  The  nitrates  (N03)  suggest 
past  or  distant  pollution.  Chlorine  suggests  remote  urinary 
contamination,  though  in  interpreting  these  results  one  must 


128  PRACTICAL   PREVENTIVE    MEDICINE 

bear  in  mind  the  so-called  normal  chlorine,  i.e.,  the  chlorine 
normally  present  in  water,  which  is  derived  from  sea  spray  or 
salt  deposits. 

(i)  Bacterial. — From  a  hygienic  standpoint  the  information 
secured  by  a  bacterial  examination  of  water  is  probably  of 
greatest  assistance  and  hence  of  greater  value  than  any  other 
determination.  Unfortunately,  since  the  sources  vary  so 
widely,  it  is  impossible  to  establish  numerical  standards  of  the 
number  of  bacteria  permissible.  The  greatest  value  of  the 
numerical  determination  of  bacteria  in  water  is  in  the  study  of 
surface  waters  or  in  the  control  of  purification  plants.  The 
detection  of  fecal  bacteria  is  of  greatest  hygienic  value  since  they 
give  evidence  of  recent  contamination.  The  group  of  colon- 
like bacilli  are  the  chief  ones  sought.  Their  detection  in  ground 
water  is  of  great  significance,  while  in  surface  waters  in  quanti- 
ties less  than  i  per  c.c,  their  significance  is  slight.  Owing  to 
their  extreme  dilution  and  for  other  reasons  the  detection  of 
specific  pathogenic  organisms  in  water  is  not  practicable.  The 
detection  of  bacteria  characteristic  of  feces  indicates  that  fecal 
contamination  is  occurring,  which  also  indicates  that  the  ex- 
creta from  an  individual  discharging  specific  infective  agents 
might  as  easily  gain  introduction. 

It  is  impossible  to  form  an  accurate  idea  of  the  hygienic 
character  of  a  water  supply  from  single  isolated  examinations. 
The  character  of  raw  natural  waters,  particularly  surface 
waters,  is  subject  to  considerable  fluctuation,  while  the 
operations  of  a  water  purification  plant  can  only  be  accurately 
controlled  by  frequent  routine  examinations  of  the  water.  Fur- 
thermore, contamination  of  a  supply  deemed  to  be  above 
suspicion  may  actually  occur,  and  unless  its  quality  is  regularly 
followed  by  laboratory  examination,  an  epidemic  may  be  the 
first  indication  of  an  unnoted  contamination.  Such  periodic 
routine  examinations  should  be  at  least  daily  at  water  purifi- 
cation plants,  and  with  untreated  water  from  satisfactory 
sources,  at  not  less  than  weekly  intervals. 

A  rigid  bacterial  standard  for  potable  waters  is  the  Treasury 
Department  standard  for  water  furnished  common  carriers  in 
interstate  traffic.     It  is  as  follows : 

(a)  The  total  bacteria  per  cubic  centimeter  shall  not  exceed 
ioo,  when  inoculated  into  standard  agar  and  incubated  at 
37  degrees  C.  for  24  hours. 

(b)  Not  more  than  one  out  of  five,  10  c.c.  portions  of  any 
sample  shall  show  the  colon  bacillus. 


RELATIONSHIP    OF    WATER    TO    HEALTH    AND    DISEASE       I  29 

A  water  that  meets  these  requirements  is  probably  from  a 
satisfactory  source,  but  on  the  other  hand,  the  standard  is  so 
rigid  that  water  from  many  safe  sources  of  supply  would  be 
excluded. 

The  following  are  suggested  by  Bartow  as  the  permissible 
limits  for  impurities  in  Illinois  waters,  expressed  in  parts  per 
million  (P.P.M). 

TABLE  IV 


Characteristic 


Lake 
Michigan 

Streams 
(Fil- 
tered) 

Springs 

and 

shallow 

wells 

Deep 
drift 
wells 

None 

IO. 0 

*None 

*None 

None 

O.  2 

*None 

*None 

None 

None 

None 

None 

150.0 

300.0 

500.0 

500.0 

4-5 

6.0 

150 

150 

0.01 

0.05 

0.02 

0.02-3 

0.08 

015 

0.05 

0.20 

0.04 

°-5 

2.0 

0.5 

None 

None 

None 

0.005 

100 

500 

500 

100 

Absent 

Absent 

Absent 

Absent 

Deep 
rock  wells 


Turbidity 

Color 

Odor 

Residue  on  evaporation 

Chlorine 

N  as  free  ammonia 

N  as  albuminoid  ammonia. .  . 

N  as  nitrates 

N  as  nitrates 

Bacteria  per  1  c.c.  2o°C 

Colon  bacillus 


*None 
*None 
None 
500.0 
5 .0-100 
0.02-3 
0.15 
°-5 
0.000 
100 
Absent 


None  as  drawn,  developes  on  standing. 


6.  Water  Consumption. — The  water  consumption  in  cities 
where  a  municipal  supply  is  available  under  pressure  in  the 
majority  of  dwellings,  when  considered  on  a  per  capita  basis 
is  quite  variable,  ranging  from  25  to  370  gallons  and  perhaps 
averaging  somewhere  near  120  gallons  per  capita  per  day.  It  is 
ordinarily  considered,  that  per  capita,  common  domestic  uses 
require  from  ten  to  seventeen  gallons  daily.  The  difference 
in  the  above  figures  is  due  to  the  use  of  water  in  manufacturing, 
irrigation,  and  losses  by  wastage.  In  European  cities  the  per 
capita  consumption  is  much  lower,  varying  from  24  to  69  in 
a  number  of  larger  cities,  and  perhaps  averaging  about  40 
gallons.  These  figures  probably  represent  an  unduly  low  con- 
sumption of  water,  but  on  the  other  hand,  the  American  figures 
undoubtedly  represent  a  serious  waste  of  this  indespensible 
necessity.  Our  aim  should  be  to  encourage  a  generous  use  of 
water,  but  to  discourage  waste. 
9 


130  PRACTICAL    PREVENTIVE    MEDICINE 

REFERENCES 

Standard  Mthods  of  Water  Analysis.     Am.  Pub.  Health  Ass'n.,  191 7. 

Hazen:  Clean  Water  and  How  to  get  it. 

Rosenau:  Perventive    Medicine    and    Hygiene.     3rd.    Ed.,    pp.   912-954. 

pp.  789-877. 
Sewage  Pollution  of  Streams.     Reprint  362,  Public  Health  Reports. 
See  also  the  list  of  water  supply  papers  of  tee  U.  S.  Geological  Survey. 


CHAPTER  XVI 

WATER  PURIFICATION 

i.  The  undesirable  qualities  which  water  may  possess  and 
the  means  available  for  their  removal  are  presented  in  the 
following  table: 


Undesirable  quality 

Removal  for  industria 

uses 

Removal  for  domestic  uses 

{a)  Hardness. 

i.  Temporary 

Lime  and  soda  ash; 
mutit. 

per- 

Boiling  or  soap. 

2.  Permanent. 

Lime  and  soda  ash; 

per- 

Lime  and  soda  ash;  per- 

mutit ;    distillation 

and 

mutit;    distillation    and 

condensation. 

condensation. 

(b)  Undesirable    metals. 

I.  Iron 

Precipitation  with  lime 
and  rapid  sand  infiltra- 
tion.    Aeration. 

2.  Lead 

Neutralization   with  lime 

and  filtration. 

(c)  Odors  and  tastes  (Al- 

gal)  

(see  Fig.  30) 
Coagulation    and 

Aeration. 

(d)  Color 

rapid 

Coagulation     and     rapid 

sand  nitration. 

sand  filtration. 

(e)  Turbidity 

Sedimentation,    coagula- 

Coagulation    and     rapid 

tion     and    rapid 

sand 

sand  filtration. 

filtration. 

(/)   Bacterial  removal. . .  . 

Storage;     sedimentation; 
rapid  and  slow  sand  fil- 
tration; domestic  niters. 

(g)  Bacterial  destruction. 

Boiling;  use  of  bleach; 
chlorine;  and  ultra-violet 
light. 

(h)  Algal  destruction  (see 

, 

Fig.  29) 

Copper  sulphate. 

Owing  to  limitations  of  time  and  space  we  will  not  give  fur- 
ther consideration  to  the  methods  for  the  removal  of  hardness 
or  undesirable  metals,  but  only  consider  the  others. 


131 


132 


PRACTICAL    PREVENTIVE    MEDICINE 


2.  Storage. — The  storage  of  water  in  large  impounding  reser- 
voirs or  lakes  for  several  months  effects  a  removal  of  any  in- 


Fig.  29. — Applying  copper  sulphate  for  the  destruction  of  algae  at  St.  Paul. 
Note  the  bag  containing  the  copper  hung  over  the  stern  of  the  boat.  {Huff 
and  House,  Jour.  Am.  W.  W.  Ass'n.,  1916.) 


Fig.  30. — Aeration  of  Hemlock  Lake  water  at  Rochester,  N.  Y.,  resulting  in  a 
reduction  of  tastes  and  odors.      (Courtesy  of  Mr.  Emit  Kuichling.) 

fective  agents  present,  by  their  exposure  to  an  unfavorable  en- 
vironment. We  have  already  called  attention  to  the  fact  that 
the  survival  of  pathogenic  micro-organisms  in  water  is  but  for 


WATER   PURIFICATION 


*33 


a  short  period.  They  are  exposed  to  the  direct  action  of  the 
sun's  rays  and  they  are  devoured  by  predatory  organisms,  of 
which  the  infusoria  are  probably  the  most  important.  One 
months  storage  under  these  circumstances  will  result  in  their 
destruction.  The  greatest  drawback  to  the  employment  of  this 
method  is  the  fact  that  sufficient  space  in  the  shape  of  a  reservoir 
is  frequently  not  available  so  as  to  permit  a  city  to  store  a  month's 
supply,  or  else  a  sufficient  reserve  of  water  is  not  available  to 
permit  its  aging  for  a  month  before  consumption  (Fig.  31). 

3.  Sedimentation. — The  lowering  of  the  velocity  of  a  stream, 
such  as  that  effected  when  it  enters  a  lake  or  reservoir,  permits 
the  fine  suspended  particles  to  settle  to  the  bottom.  The  finer 
the  particles,  the  lower  must  be  the  velocity  and  the  longer  the 


Fig.  31. — Lake  Cheesman  dam  and  reservoir.  Denver  Union  Water  Com- 
pany. A  large  impounding  and  storage  reservoir.  (Hazen:  "Clean  Water  and 
How  to  Get  It,"  John  Wiley  and  Sons.) 

quiescent  period  before  their  removal  is  effected.  This  method 
in  itself  is  used  chiefly  as  a  means  of  removing  turbidity,  and 
is  of  but  slight  value  in  the  removal  of  bacteria  unless  the 
period  of  quiescence  approximates  the  conditions  of  storage. 
Large  open  tanks  or  reservoirs  are  employed  for  sedimentation. 
Sedimentation  maybe  employed  in  conjunction  with  the  process 
of  coagulation. 

4.  Coagulation  is  used  in  conjunction  with  sedimentation  or 
as  a  process  of  treatment  preliminary  to  rapid  sand  filtration. 
It  is  a  necessary  measure  to  remove  the  fine  turbidity,  parti- 
cularly that  produced  by  colloidal  clay,  which  would  not 
completely  settle  out  no  matter  how  long  the  period  of  sedi- 
mentation.    Coagulation  consists  in  the  employment  of  cer- 


134 


PRACTICAL  PREVENTIVE  MEDICINE 


tain  chemicals,  such  as  sulphate  of  aluminum,  which  react 
with  the  alkaline  carbonates  of  the  water  to  form  aluminum 
hydrate.     This  has  a  large  colloidal  molecule  and  being  in- 


FiG.  32. — Sedimentation  and  coagulation  basins  at  Louisville.  Note  the 
iong  vertical  partitions  or  baffles  which  reduce  the  velocity  of  the  water  in  passing 
through  the  basins.      (Water-supply  Paper  315,  U.  S.  Geological  Survey.) 

soluble,  is  thrown  out  of  solution  as  a  coarse,  flocculent  pre- 
cipitate in  which  most  of  the  suspended  matter  and  bacteria 
become  enmeshed  (Fig.  32). 


WATER    PURIFICATION 


135 


In  practice  only  sufficient  alum  is  added  to  combine  with  the 
carbonates,  so  that  no  alum  remains  in  solution  and  all  of  the 
precipitate  is  removed  (Fig.  40).  Iron  sulphate  is  similarly 
used.  If  sufficient  carbonates  to  break  up  the  alum  are  not 
present  normally,  the  required  alkalinity  is  secured  by  the 
addition  of  lime  or  soda  to  the  water. 

5.  Slow  Sand  Filtration. — This  is  accomplished  by  large 
filters,  either  open  or  covered,  each  about  an  acre  in  extent 
(Fig.  33)  consisting  of  collecting  tiles  overlain  with  gravel  and 

1 


Fig.  33. — Bird's  eye  view  of  the  covered  slow  sand  filters  at  Providence 
showing  the  pumping  station,  laboratory,  filter  roofs  and  the  storage  of  dirty 
sand.      (1910  Rep.  Providence  City  Engineer.) 

coarse  sand  (Fig.  34).  These  are  operated  with  ahead  of  from 
two  to  four  feet  of  water  above  the  sand  (Fig.  35).  Bacterial 
removal  is  not  accomplished  by  any  straining  action  of  the  sand 
grains,  but  by  the  development  of  algse  and  protozoa  in  the 
surface  layers  of  the  sand,  which  reduce  the  interstices  still 
further  and  prey  upon  bacteria.  When  this  biological  film  is 
sufficiently  developed  the  water  passing  a  filter  is  used.  Under 
these  conditions  it  is  so  operated  as  to  permit  the  passage  of 
from  2.5  to  5  million  gallons  of  water  per  acre  per  day.  The 
biological  film  continues  to  develop  during  the  course  of  several 


136 


PRACTICAL    PREVENTIVE    MEDICINE 


weeks  to  such  an  extent  that  the  passage  of  water  gradually 
becomes  seriously  hindered,  whereupon  the  filter  is  drained,  and 
the  top  layer  of  sand  is  removed  (Fig.  36).  After  cleaning,  the 
filter  is  again  placed  in  commission  and  the  process  of  cleaning 
is  repeated  as  often  as  necessary.  When  the  sand  layer  is  re- 
duced to  12  to  18  inches  in  depth,  the  filter  is  drained  and  the 
sand,  which  in  the  meantime  has  been  washed,  is  restored  to 
the  filter  (Fig.  37). 

Preliminary  methods  of  treatment  are  not  required,  although 
the  process  is  not  adapted  to  turbid  water.     The  first  cost  of 


43  iltf*** ..••■■■ 


iiia--*1- 


m** 


«.*•*" 


,«*»«« 


a,*,**'*^ 


Fig.  34. — Cross-section  of  a  typical  slow  sand  filter.  Note  the  under  drains, 
which  are  of  an  uncommon  type,  the  layer  of  superimposed  gravel,  and  the  thick 
layer  of  coarse  sand.      (Mason,  "  Water  Supply,"  John  Wiley  and  Sons.) 

installing  such  a  filter  plant  is  large,  but  the  operating  cost  is 
low.  The  filter  accomplishes  a  bacterial  removal  of  about  99  per 
cent,  and  is  extremely  uniform  in  its  action. 

6.  Rapid  Sand  Filtration. — -This  is  accomplished  by  two  types 
of  filters,  either  pressure  or  gravity,  according  to  the  manner 
in  which  the  head  of  water  is  secured  upon  the  filter.  The 
operation  of  each  is  based  upon  the  same  principle.  This 
method  requires  only  a  small  installation,  with  a  low  initial 
cost,  but  a  high  cost  of  maintenance.     They  are  very  efficient 


WATER    PURIFICATION 


J37 


in  the  removal  of  color  and  turbidity,  and  slightly  less  efficient 
(95  per  cent,  to  99  per  cent.)  and  less  uniform  in  the  degree  of 
bacterial  removal  secured  as  compared  with  slow  sand  niters. 
Filtration  is  effected  by  the  formation  of  a  thin  film  of  the 
precipitated  coagulant  upon  the  surface  of  the  sand  through 
which  the  water  passes,  either  by  gravity  or  pressure.  Since 
the  film  of  precipitate  held  back  by  the  sand  is  constantly 
increasing,  the  amount  of  water  which  passes  through  is  soon 
finally  reduced  below  efficient  limits.  When  this  occurs,  usually 
every  6  to  12  hours,  the  filter  is  disconnected  and  the  precipi- 


FiG.  35. — Filter  bed  No.  6,  Indianapolis  Water  Company.  This  illustration 
shows  the  smooth,  clean  surface  of  the  sand  in  a  filter  bed  which  is  ready  for 
water  to  be  admitted.      The  water  covers  the  sand  to  a  depth  of  about  four  feet. 


tate  removed  by  reversing  the  flow  of  water,  and  agitating  the 
sand,  either  by  means  of  compressed  air  or  mechanical  rakes 
(Figs.  39,  42).  The  dirty  wash  water  is  wasted.  When  the 
sand  is  cleaned,  the  reverse  flow  is  stopped,  the  sand  settles 
into  place  over  the  gravel,  and  the  coagulant  containing  water 
is  again  sent  through  the  filter.  These  filters  are  operated  at 
the  rate  of  ioo  to  150  million  gallons  per  acre  per  day,  hence 
the  small  installations. 

Sedimentation  to  remove  some  of  the  precipitated  coagulant 


138 


PRACTICAL   PREVENTIVE    MEDICINE 


is  usually  used  as  a  preliminary  process,  in  order  to  prevent  the 
too  rapid  clogging  of  the  filters. 

The  gravity  filters  are  open  vats  or  reservoirs  or  wood  or  con- 
crete (Fig.  41),  while  the  pressure  filters  are  cylindrical  steel 
tanks  (Figs.  38,  39). 

7.  Disinfection  of  Water. — In  this  country  chlorine  is  the 
only  agent  extensively  employed  for  this  purpose,  and  is  ap- 
plied either  as  liquid  chlorine  or  a  solution  of  bleaching  powder. 
Disinfection  is  applied  as  a  finishing  process  to  water  that  has 


Pig.  36. — Filter  bed  No.  i,  Indianapolis  Water  Company.  This  shows  work- 
men cleaning  or  scraping  a  filter  bed  to  remove  the  muddy  upper  layer  of  sand 
containing  the  impurities  trom  the  water.  The  sand  is  thrown  into  piles  previous 
to  being  removed  for  washing. 

been  previously  filtered  or  otherwise  clarified.  The  value  of 
the  process  from  the  standpoint  of  the  destruction  of  the  bac- 
teria which  pass  through  the  filters,  including  pathogenic  and 
non-pathogenic  germs,  has  been  well  demonstrated.  From  .1 
to  .5  parts  per  million  of  available  chlorine  are  commonly  em- 
ployed, requiring  the  addition  of  about  5  to  12  pounds  of  bleach 
per  million  gallons  of  water.  Quantities  of  bleach  in  excess  of 
25  pounds  can  be  detected  by  taste.  Of  recent  years  the  employ- 
ment of  liquid  chlorine  has  been  superseding  bleach,  owing  to  the 
lesser  cost  of  the  former,  as  well  as  its  convenience  (Fig.  43) .    The 


WATER    PURIFICATION 


J39 

'1 


Fig.  37. — Sand  washing  machine,  Indianapolis  Water    Company.     Sand  being 
removed  from  filter  bed,  washed  and  stored  by  hydraulic  machinery. 


Fig.  38. — Mechanical  filters  at  Chattanooga,  Tenn.  Note  the  vertical  shafts 
at  the  top  of  each  pressure  filter  unit.  To  these  shafts  are  connected  the  revolv- 
ing rakes  which  agitate  the  sand  when  the  filter  is  washed.  The  shafting  re- 
volves the  rakes.  It  is  because  of  these  connections  that  pressure  filters  are 
sometimes  called  mechanical  filters.  (Courtesy  of  American  Water  Works  and 
Guarantee  Company.) 


140 


PRACTICAL   PREVENTIVE    MEDICINE 


Pig.  39. 


-Schematic  view  of  a  typical  rapid  sand  filter  of  the  pressure  type. 
(Mason,  "Water  Supply,"  John  Wiley  and  Sons.) 


L 

Fig.  40. — Coagulant  storage  and  feeding  devices  at  Scranton.  The  coagu- 
lant solutions  are  stored  in  the  tanks  on  the  platform,  and  fed  into  the  raw  water 
by  means  of  the  constant  head  device  on  the  floor  below.  (Water  Supply  Paper 
315.      U.  S.  Geological  Survey.) 


WATER   PURIFICATION 


141 


amount  required  is  greater  when  the  content  of  the  water  in 
organic  matter  is  high.     Disinfection  is  probably  accomplished 


Fig.  41. — Interior  of  the  gravity  type  filter  house  at  Little  Falls.  The  filter 
units  are  observed  beyond  the  railing  at  either  side.  The  operation  of  each 
filter  unit  is  controlled  by  means  of  electrically  operated  valves,  manipulated 
from  the  table  in  front  of  each  filter.      (Courtesy  of  Mr.  G.  W.  Fuller.) 


Fig.  42. — A  gravity  filter  unit  at  Watertown,  N.  Y.,  with  the  sand  and  gravel 
removed.  Note  the  strainers  and  piping  for  collecting  the  filtered  water,  the 
pipes  for  the  compressed  air  used  to  agitate  the  sand  in  washing,  and  the  wooden 
troughs  at  the  top,  which  carry  the  waste  wash  water  away.  (Hazen:  "Clean 
Water  and  How   to  Get  It,"  John  Wiley  and  Sons.) 

by  nascent  oxygen  liberated  by  the  hypochlorous  acid  formed 
by  the  mixture  of  the  bleach  with  the  water. 


142 


PRACTICAL    PREVENTIVE    MEDICINE 


MANUAL  CONTROL  CHLORINATOR 
SOLUTION  FEED  -  TYPE  >S, 


Fig.  43. — Photograph  and  diagram  of  a  typical  device  for  the  disinfection 
of  water  by  liquid  chlorine.      (Wallace  and  Tiernan  Co.,  New  York.) 

I,  Chlorine  absorption  chamber;  K—L,  chlorine  solution  line;  V,  water  con- 
nection; P,  water  valve;  R,  gauge;  O,  water  valve  to  water  seal  N;  T,  water  spill; 
U,  chlorine  solution  line  to  point  of  application;  N,  water  seal;  Size,  apparatus 
mounted  in  wall  cabinet  20  X  21  inches;  S,  control  valve;  A,  chlorine  tank;  B, 
valve  on  chlorine  tank;  C,  auxiliary  valve;  D,  flexible  connection;  E,  pressure 
compensating  valve  for  taking  care  of  the  varying  pressures  in  the  chlorine  tank 
and  also  maintaining  a  constant  drop  in  pressure  across  the  valve  5;  S,  control 
valve;  G,  valve  to  prevent  moisture  from  getting  back  into  control  parts  of 
apparatus;  H,  valve  to  control  flow  of  water  and  to  keep  chlorine  out  of  incoming 
water  connections;  F,  pressure  gauge  showing  pressure  in  tank;  J,  chlorine  flow 
meter  (inverted  siphon  type). 


WATER   PURIFICATION 


143 


8.  Results  of  Water  Purification  and  Disinfection. — Since 
the  first  serious .  attempt  at  water  purification  in  the  United 
States  in  1872,  the  practice  has  abundantly  justified  itself  as  a 
sanitary  measure  of  the  highest  order.  Endemic  water  borne 
typhoid  has  either  been  eliminated  or  greatly  reduced  in  the 
municipalities  making  the  change.  In  Table  V  are  presented  a 
few  examples  to  show  the  typical  results  which  have  been 
secured. 

TABLE  V 
Effect  of  Water   Purification   on  Typhoid  Rates.     Average   Typhoid 
Death  Rate  per  100,000  Population  (After  Rosenau). 


City 


Average 

before 

improvement 


Average 

after 
improvement 


Percentage 
reduction 


Albany 

Elmira 

Hudson 

Ithaca 

Schenectady. 

Troy 

Watertown. . , 
Binghampton 
Rensselaer. . . . 


23-7 
4i-5 
3i-9 
14.6 
14.4 
31.0 

36.9 
11. 7 

54-4 


73-° 

24.4 

5°-5 
78.3 
42 .6 
46.8 
61.8 
72.3 
43  -o 


TABLE  VI 
Effect  of  Chlorination  on  Typhoid  Rates.     Average  Typhoid  Death  Rate 
per  100,000  Population  (After  Race) 


Chlorination 
begun 

Before  using 

After  using 

Percentage 

City 

Period 

Rate 

Period 

Rate 

reduction 

Baltimore 

Cleveland 

Des  Moinss 

Erie 

June,  1911 
Sept.,  1911 
Dec,  1910 
March,  1911 
Dec,  1911 
Sept.,  1908 
Jan.,  1911 
May,  1910 
Dec,  1911 
Feb.,  1910 
April,  191 1 
Sept.,  1912 

1900-10 
1900-IO 
1905-10 
1906-10 
1 908- 1 1 
1900-17 
1900-10 
1900-09 
1907-H 
1906-10 
1906-IO 
1906-10 

35-2 
35-5 
22 . 7 
50.6 
29.0 
18.7 
42.5 
22.5 
46.0 
40.0 
31.2 
34 -° 

1912-15 
1912-16 
1911-13 
1912-14 
1912-13 
1909-16 
1911-16 
1911-16 
1911-14 
1911-16 
1912-16 
1913-17 

22  .  2 
8.2 

13-4 
15.0 

14-5 

8.4 

14.2 

10.6 

28.7 

25.0 

7.8 

17.0 

36 

77 
41 
70 

Evanston,  111 

Jersey  City 

Kansas  City,  Mo. 

Omaha,  Neb 

Trenton 

5° 
SS 
66 

53 
35 

Montreal 

Toronto 

37 

75 

Ottawa 

50 

144 


PRACTICAL    PREVENTIVE    MEDICINE 


Though  a  much  more  recent  development,  the  reduction  in 
typhoid  rates  effected  by  chlorination  of  water  are  every  bit  as 
striking  as  those  secured  by  purification.  The  experience  of  a 
few  cities  is  summarized  in  Table  VI. 

TABLE  VII 
Typhoid  Fever  in  Burlington,  Vermont 


Year 

Death  rates  per  100,000  from  typhoid  fever, 

1904 

36 

I90S 

34 

1906 

43 

1907 

23 

1908 

20  (Mechanical  filter  plant  opened  in  April). 

1909 

25 

1910 

n  (Bleach  applied  to  water  in  April). 

1911 

7 

1912 

4 

Evidence  is  accumulating  to  indicate  that  purification  in 
itself  did  not  succeed  in  completely  eliminating  water  borne 
typhoid.  Cities  which  experienced  a  reduction  in  their  typhoid 
rates  following  the  installation  of  a  purification  plant  experi- 
enced a  still  further  reduction  after  the  inauguration  of  dis- 
infection.    An  example  of  this  experience  is  shown  in  Table  VII. 

In  addition,  several  instances  have  been  observed  of  typhoid 
and  dysentery  outbreaks  following  emergencies  when  purifica- 
tion plants  were  temporarily  shut  down  because  of  floods  or 
accidents. 

In  addition  to  affecting  a  reduction  in  the  typhoid  death  rate, 
Mills  and  Reincke  noted  (Mills-Reincke  phenomenon)  that 
following  the  improvement  in  a  water  supply  by  the  introduc- 
tion of  purification  processes,  there  is  not  only  a  drop  in  the 
typhoid  death  rate,  but  a  drop  in  the  general  death  rate  as  well. 
From  studies  by  McLaughlin  it  would  appear  this  decline  is 
due  to  a  decrease  in  infantile  deaths  from  diarrhea. 

The  type  of  purification  process  or  processes  best  adapted  to 
a  given  source  of  water  supply,  as  well  as  the  source  of  a  con- 
templated municipal  supply  itself,  had  best  be  selected  by 
competent  sanitary  engineers  after  careful  study  has  been  made 
of  the  source,  its  probable  ability  to  supply  the  demands  of  a 
growing  population  for  the  next  twenty  or  thirty  years  and  the 
character  of  the  impurities  whose  removal  is  necessary. 


WATER    PURIFICATION 


145 


9.  Domestic  Water  Supplies  (Figs.  44,  45,  46,  47). — These 
include  wells,  springs,  and  cisterns.  It  is  important  to  remember 
that  with  these  the  danger  of  contamination  is  practically 
exclusively  from  surfaces  sources.  They  should  therefore  be 
protected  from  surface  drainage,  and  have  tight  water-proof 
tops.     They  should   also  be  located   a   considerable  distance 


WATE.R    BEARING 
■V-'.'SAND 


Fig.  44. — Showing  how  pollution  may  enter  an  improperly  located  and  poorly 
constructed  well.  Most  contamination  of  wells  enters  from  the  top.  Note  the 
drainage  toward  the  well.      {Minn.  State  Board  of  Health.) 


from  sewers,  privies  and  cess  pools.  Underground  contamina- 
tion may  occur  in  clayey  or  gravely  soils  or  in  limestone  regions, 
owing  to  the  fissured  or  open  character  of  the  sub-soil.  Shallow 
wells  are  frequently  contaminated. 

10.  Emergency  Protection  in  the  Home. — The  various  do- 
mestic filters  are  of  little  value,  as  in  order  to  give  satisfactory 
results  they  must  be  cleaned  frequently,  at  least  daily,  and  it 


10 


146 


PRACTICAL    PREVENTIVE    MEDICINE 


is  rare  for  them  to  receive  this  care.     They  are  apt  to  give  a 
false  sense  of  security. 

Boiling  drinking  water  from  15  to  20  minutes  is  one  of  the 
best  emergency  safeguards  that  can  be  employed.  Another 
method  of  equal  value  is  the  employment  of  bleach  or  chlori- 


WATER     BEARING^ 
SAND  OR  GRAVEL 


Pig.  45. — Showing  how  a  well  can  be  protected  against  pollution.      (Minn.  State 

Board  of  Health.) 

nated  lime.  A  stock  solution  of  bleach  is  made  by  adding  one 
teaspoonful  of  fresh  chlorinated  lime  to  a  pint  of  water.  •  This  is 
added  to  the  drinking  water  in  the  proportion  of  one  teaspoonful 
to  ten  gallons,  or  nine  drops  to  one  quart,  and  allowed  to  act 
for  15  to  30  minutes  before  the  water  is  consumed. 

REFERENCES 


Race:  Chlorination  of  Water. 

Stein:  Water  Purification  Plants  and  Their  Operation. 


WATER    PURIFICATION 


147 


e_^  g  ^rp$j:>  |;  .-^5? 


Pig.  46. — Showing  how  a  spring  can  be  protected  against  pollution.    (Minn. 
State  Board  of  Health.) 


148 


PRACTICAL  PREVENTIVE  MEDICINE 


Johnson:  The  Purification  of  Public  Water  Supplies.     Water  Supply  Paper 

No.  315,  U.  S.  Geological  Survey. 
Freeman:  Good  Water  for  Farm  Homes.     Public  Health   Bulletin    Xo.  70 

U.  S.  Public  Health  Service. 
Farm  Water  Supplies.     Bulletin  Minnesota  State  Board  of  Health. 
Rosen atj:  Preventive  Medicine  and  Hygiene.     3rd  Ed.,  pp.  878-911. 


Fig.  47. — Showing  a  properly  constructed   cistern  located   outside   the  house. 
{Minn.  State  Board  of  Health.) 


The  Chemical  Disinfection  of  Water.     Reprint  225,  Public  Health  Reports. 

Hypochlorite  Treatment  of  Water  Supplies.  Reprint  261,  Public  Health 
Reports. 

Water  Supply,  Plumbing  and  Sewage  Disposal  for  Country  Homes.  Bulle- 
tin 57,  U.  S.  Department  of  Agriculture. 

Whipple:  The  Microscopy  of  Drinking  Water. 


CHAPTER  XVII 
PRODUCTION  AND  INSPECTION  OF  MILK 

i.  Of  all  substances  consumed  as  food  the  position  of  milk 
is  unique.  And  of  course  in  the  northern  temperate  latitudes 
when  we  speak  of  milk  one  naturally  understands  that  cows 
milk  is  understood.  It  owes  its  unique  position  to  the  following 
circumstances  as  pointed  out  by  Rosenau: 

(i)  It  is  the  only  standard  article  of  diet  obtained  from 
animal  sources  that  is  ordinarily  consumed  in  its  raw  state; 
i.e.,  it  is  not  ordinarily  heated  in  some  cooking  process  prior  to 
^consumption. 

(2)  Its  peculiar  composition  renders  it  highly  suitable  as  a 
medium  for  a  wide  variety  of  micro-organisms,  both  pathogenic 
and  non-pathogenic. 

(3)  The  foregoing  characteristics  subject  milk  to  rapid 
changes  as  a  result  of  the  activity  of  the  micro-organisms,  some 
of  which  may  produce  decompositions  that  render  the  milk 
unfit  or  even  dangerous  as  food.  As  a  consequence  of  these 
decompositions  the  original  character  of  the  milk  may  be  largely 
lost  or  markedly  altered. 

(4)  The  conditions  of  the  production  and  the  activity  of 
micro-organisms  make  milk  the  most  difficult  of  all  animal  foods 
to  obtain,  to  handle,  to  transport  and  to  deliver  in  a  clean, 
fresh  and  satisfactory  manner. 

These  peculiarities  serve  to  indicate  the  important  relation- 
ship which  milk  possesses  to  both  health  and  disease.  Thus: 
(1)  As  a  result  of  the  favorable  environment  it  creates  for 
micro-organisms,  it  may  serve  as  an  important  route  for  the 
dissemination  of  several  species  of  infective  agents;  (2)  Devised 
as  it  is  by  nature  as  the  first  food  for  the  calf,  it  serves  nearly 
equally  as  well  as  food  for  the  young  of  the  human  species  as 
well  as  for  human  adults,  due  to  the  proportion  in  which  the 
different  food  elements  are  present.  But  on  the  other  hand, 
when  its  composition  is  altered  by  microbial  activity  arising 
from  improper  care,  it  may  become  a  dangerous  instead  of  a 
safe  food;  (3)  In  addition  to  possessing  all  the  different  food 
elements  in  its  composition,  the  elements  are  present  in  proper 
relative  proportions,  so  that  milk  may  be  said  to  be  the  only 

149 


150  PRACTICAL   PREVENTIVE   MEDICINE 

properly  balanced  food.  Furthermore  all  the  different  sub- 
stances present  are  readily  digestible.  If  one  tends  to  tire 
of  a  milk  diet,  the  monotony  may  be  relieved  by  some  of  the 
numerous  modifications  which  the  cook  or  housewife  may 
devise. 

2.  Sophistication  of  Milk. — Unscrupulous  dairymen  the 
world  over  make  a  more  or  less  frequent  practice  of  altering  the 
milk  they  retail,  either  by  abstracting  the  more  valuable  con- 
stituents, such  as  the  butter  fat,  or  by  adding  diluents  or  en- 
deavoring to  conceal  changes  of  decomposition,  or  to  prevent 
decomposition  by  improper  methods.  Under  these  headings 
come  the  practices  of  skimming,  watering,  adding  of  skimmed 
milk,  thickening,  coloring  and  the  addition  of  alkalies  or  of 
chemical  preservatives. 

These  practices  are  unjustifiable  and  fraudulent,  but  since 
the  health  of  the  consumer  is  as  a  general  rule  unaffected, 
though  his  pocket  book  is  depleted  by  fraud,  we  must  regard 
this  question  as  of  economic  importance  rather  than  of  sanitary 
importance.  The  only  situation  where  the  health  of  individuals 
might  suffer  as  a  consequence  is  in  situations  where  milk  of  a 
certain  composition  is  desired,  as  for  example,  for  the  feeding  of 
tuberculous  patients  or  of  infants,  with  whom  it  would  consti- 
tute the  principal  article  of  the  diet. 

3.  Source  of  Micro-organisms  in  Milk. — The  hygienic  im» 
portance  of  milk  is  closely  related  to  its  microbial  content, 
not  that  the  myriads  of  micro-organisms  which  thrive  in  milk 
are  in  themselves  necessarily  harmful,  but  rather  the  extent  of 
their  abundance  gives  important  information  relative  to  the 
age  of  the  milk,  the  degree  of  care  exercised  in  its  production 
and  handling,  and  the  conditions  under  which  it  has  been 
stored.  It  must  be  borne  in  mind  that  an  exact  or  even  a  fairly 
close  approximate  determination  of  the  number  of  bacteria  per 
unit  volume  of  milk  cannot  be  secured,  and  that  the  best  re- 
sults are  only  in  reality  approximations.  Furthermore  the 
enumerations  secured  vary  with  the  technic  employed.  An 
exposition  of  these  phases  of  bacteriologic  procedure  would  be 
too  extensive  for  presentation  here,  so  reference  must  be  made 
to  other  sources  of  information. 

Since  the  questions  of  production,  handling,  storage  and 
age,  closely  affect  the  microbial  content  of  milk,  it  is  necessary 
to  consider  their  influences. 

(1)  Production  and  Handling. — The  amount  of  fresh  milk 
consumed  daily  in  this  country  is  enormous.     Practically  all 


PRODUCTION   AND   INSPECTION   OF   MILK 


151 


the  milk  of  this  supply  is  furnished  by  small  producers,  the 
majority  of  whom  at  present  have  no  special  knowledge  of  the 
conditions  necessary  for  the  production  of  a  hygienic  milk,  or 
the  facilities  to  apply  such  knowledge.  The  milk  supply  of 
the  large  centers  of  population  is  secured  from  the  small  pro- 
ducers within  a  radius  of  from  100  to  200  miles  and,  owing  to 
transportation  difficulties,  may  be  thirty  six  hours  old  when  it 
reaches  the  consumer.  On  the  other  hand  with  the  smaller 
cities  and  towns  the  radius  of  production  is  narrower  and  the 
consumer  seldom  gets  milk  24  hours  of  age  and  usually  less. 


Fig.  48. — Dirty  flanks.  A  common  condition  in  winter.  Flanks  become 
caked  with  manure,  which  there  is  often  no  thought  of  removing.  This  is  the 
source  of  the  dirt  found  in  milk  in  winter  time.  (Webster,  Bull.  No.  56,  Hygienic 
Laboratory.) 


The    principal    sources    from    which    micro-organisms    gain 
introduction  are  the  following: 

1.  The  udder  and  teats  of  the  cow,  as  well  as  their  flanks  and 
bellies  (Fig.  48). 

2.  The  hands  of  the  milker. 

3.  Dirt  and  dust  of  the  stables  (Figs.  50,  51). 

4.  Cow  manure  (Fig.  48). 

5.  Milking  utensils. 

Of  these  the  first,  fourth  and  fifth  are  probably  of  greatest 


*52 


PRACTICAL   PREVENTIVE   MEDICINE 


importance.  In  general  it  may  be  said  that  the  presence  of 
micro-organisms  is  closely  associated  with  the  introduction  of 
dirt,  particularly  cow  manure,  which  commonly  gains  introduc- 
tion from  the  teats,  udder  and  flanks  of  the  cow  by  dropping  into 
the  milking  pail  (Fig.  49).  It  is  therefore  apparent  that  a 
milking  pail  with  a  small  top  will  prove  of  material  assistance 
in  reducing  the  amount  of  dirt  that  gains  entrance  (Fig.  59). 
In  addition  the  thorough  brushing  of  the  cows  with  brush  and 
curry  comb  (Fig.  52)  followed  by  a  wiping  with  a  damp  cloth, 


Fig.  49. — Sediment  disks  showing  from  o.oi  to  0.5  gram  of  fresh  manure  removed 
from  different  bottles  of  milk.      (Bull-  642,  U.  S.  Dept.  of  Agriculture.) 


largely  eliminates  gross  dirt  from  the  milk  pail.  The  character 
of  the  milk  pails  and  utensils  is  of  importance  from  another 
standpoint.  If  their  interior  is  rusty  or  their  seams  rough, 
their  cleaning  is  made  difficult.  Milk  remains  in  the  recesses 
in  which  bacteria  multiply  and  which  serve  as  cultures  to  seed 
the  fresh  milk  when  the  utensils  are  again  in  use  Hence  in 
addition  to  possessing  small  tops,  the  milk  pail  should  have  a 
smooth  interior  and  be  subjected  to  sterilization  after  clean- 
sing.    For  this  purpose  streaming  steam  is  very  effective.  (Fig 

57). 


PRODUCTION   AND   INSPECTION   OF   MILK 


*53 


The  temperature  at  which  the  milk  is  tored  between  the  in- 
terval of  its  production  and  its  consumption  is  of  great  impor- 
tance. If  kept  at  air  temperature,  bacterial  multiplication  will 
be  rapid  and  the  milk  will  soon  spoil.  The  rapid  cooling  (Fig. 
55)  of  the  milk  after  its  drawing  and  its  maintenance  at  a 
temperature  of  io°C.  (5o°F.)  or  lower  will  largely  inhibit 
bacterial  multiplication  and  hence  prevent  decomposition. 
Practically  sterile  milk  in  commercial  quantities  cannot  be 
produced,  but  on  the  other  hand,  care  in  the  production  and 
handling  of  milk  will  keep  the  count  very  low. 


: 


Pig.  50. — Stable  yards  of  this  type  are  all  too  common.  The  cows  are  com- 
pelled to  wade  knee  deep  in  manure  in  order  to  get  into  the  stable  Much  of 
the  filth  on  legs  and  tail  from  this  source  gets  into  the  milk.  (Bull.  56.  Hygienic 
Laboratory.) 


4.  Classification  of  Milk. — From  a  hygienic  standpoint  we 
may  consider  either  of  two  classifications  of  milk,  first: 

(a)  Raw  milk,  and 

(b)  Pasteurized  milk. 

Raw  milk  includes  all  milk  that  has  not  been  heated  to  a 
temperature  sufficient  to  destroy  most  bacteria,  and  which 
at  the  same  time  will  not  alter  the  nutritional  properties  of  the 
milk.  Hygienically,  raw  milk  may  be  of  any  grade  of  the 
second  classification.     Potentially  it  is  dangerous,  since  with 


1 54 


PRACTICAL   PREVENTIVE    MEDICINE 


the  greatest  of  care  it  is  impossible  to  prevent  the  introduction 
of  infective  agents  into  some  lots. 

Pasteurization  is  a  process  of  sterilizing  or  partially  steri- 
lizing organic  solutions  without  altering  their  chemical  proper- 
ties, devised  by  Pasteur  and  first  applied  to  beer  and  wines  (Fig. 
58).  As  applied  to  milk  or  cream  three  methods  are  in  use. 
They  are  the  following: 

(a)  The  flash  method  which  from  a  hygienic  standpoint  is 
the  poorest.     It  is  used  chiefly  in  those  dairies  run  as  adjuncts 


FlG.   51. — A  dirty  stable  interior.      (Bull.  56,  Hygienic  Laboratory.) 

to  creameries,  where  the  milk  or  cream  is  heated  to  destroy 
undesirable  lactic  fermentation.  These  lactic  organisms  are 
destroyed  at  temperatures  lower  than  the  pathogenic  organisms 
likely  to  be  present,  hence  the  latter  are  not  affected.  The 
milk  is  momentarily  heated  but  the  temperature  is  not  main- 
tained. 

(b)  The  holding  process:  The  milk  is  heated  in  large  vats  and 
the  temperature  maintained  for  some  time  (Fig.  59).  The 
temperature  used  is  sufficient  to  kill  pathogenic  organisms.  At 
the  completion  of  the  process  the  hot  milk  is  cooled  by  running 


PRODUCTION   AND   INSPECTION    OF   MILK 


155 


over  cooling  coils  and  then  bottled  (Fig.  56).  The  process 
will  efficiently  destroy  infective  agents  present,  but  the  milk 
may  be  subsequently  contaminated. 

(c)  The  in-bottle  method,  which  is  a  modification  of  the 
holding  process.  The  milk  is  run  into  clean  bottles,  the  bottles 
capped  with  crown  seals  and  submerged  in  vats  of  water  which 
are  heated  to  the  desired  temperature  and  this  temperature 
maintained,  or  they  are  placed  in  closed  chambers  and  sprayed 
with  hot  water.     Various  commercial  modifications  of  the  pro- 


FiG.  52. — Cleaning  cows  preparatory  to  milking.  A  simple  operation  re- 
quiring no  other  outlay  than  a    little    time.      (Bull.  56,   Hygienic  Laboratory). 

cedure  are  in  vogue  (Figs.  60,  61).  After  heating  the  bottles  are 
cooled  and  chilled.  This  method  possesses  the  advantage  that 
subsequent  contamination  is  prevented. 

The  most  satisfactory  pasteurization  from  a  hygienic  stand- 
point is  achieved  by  holding  the  milk  from  35  to  40  minutes  at 
a  temperature  of  65  degrees  C.  (Fig.  58).  Pasteurization  does 
not  alter  the  digestibility  of  the  milk;  though  some  may  observe 
a  difference  in  its  palatability.  The  heating  alters  the  vis- 
cosity of  the  butter-fat,  so  that  a  distinct  cream  line  is  not 


i56 


PRACTICAL   PREVENTIVE    MEDICINE 


formed.     Oxidases  and  vitamines  are  destroyed,  so  that  pas- 
teurized milk  used  for  infant  feeding  should  be  supplemented 


Pig.  53. — A  clean  light,  airy  interior.  Milkers  at  work  are  dressed  in  clean 
white  suits  and  caps.  Cows  are  clean.  An  ideal  place.  (Bull.  56,  Hygienic 
Laboratory). 


Pig.  54. — Types  of  milk  pails.      Narrow-top  pails  are  best.      (Bull.  56.  Hygi- 
enic Laboratory). 

with  orange  juice  to  supply  vitamines,  otherwise  some  children 
may   develop    infantile   scurvy.     Pasteurized    milk   must    be 


PRODUCTION   AND   INSPECTION    OP    MILK 


157 


cooled  and  carefully  kept  cool,  otherwise  it  is  apt  to  putrify 
instead  of  souring,  due  to  the  destruction  of  the  lactic  ferments, 
while  the  spore  forming  proteolytic  bacteria  survive  the  heating. 
To  secure  the  maximum  protection,  all  pasteurizing  vats  should 
be  equipped  with  recording  thermometers,  and  the  process 
should  be  carried  out  under  official  supervision. 

2.  By  another  classification  milk  may  be  divided  into  three 
grades : 

(a)  Certified  milk. 


Pig.  54a. — A  good  type  of  inexpensive  milk  house.  A  milk  house,  separate 
from  the  dwelling  and  stable,  is  indispensable.  Here  the  milk  should  be  brought 
for  cooling  and  bottling,  and  here  the  milk  utensils  should  be  cleaned  and  steri- 
lized.    (Bull.  56,  Hygienic  Laboratory.) 


(b)  Inspected  milk. 

(c)  Market  milk. 

The  use  of  the  term  certified,  as  applied  to  milk,  is  limited  to 
milk  produced  in  accordance  with  the  requirements  of  the 
American  Association  of  Medical  Milk  Commissions.  For  its 
production,  the  dairyman  enters  into  a  contract  with  the 
association,  agreeing  to  the  following  conditions,  in  return  for 
which  his  milk  is  certified. 

(a)  The  producing  dairies  shall  be  periodically  inspected. 

(b)  Frequent  analysis  of  the  milk  shall  be  made. 


158 


PRACTICAL   PREVENTIVE    MEDICINE 


(c)  Pure  water  shall  be  supplied  for  dairy  use. 

(d)  The  dairy  herd  shall  be  free  from  tuberculosis  as  demon- 
strated by  frequent  inspections  and  tuberculin  tests.  In  addi- 
tion all  cows  shall  be  free  from  other  diseases  liable  to  cause 
deterioration  of  milk. 

(e)  The  stables  must  be  kept  clean  and  be  properly  ventilated 
and  lighted. 

(/)  The  cows  must  be  properly  fed  and  cared  for. 


Pig.  55. — A  very  neat,  inexpensive,  small,  bottling  room.  Note  at  the  right 
the  conical  cooler,  over  which  the  warm  milk  is  allowed  to  flow.  (Bull.  56, 
Hygienic  Laboratory.) 

(g)  All  milk  handlers  must  be  free  from  communicable  dis- 
eases. They  must  observe  scrupulous  cleanliness  in  their 
work  (Fig.  53). 

Qi)  All  care  must  be  used  in  milking,  the  milk  must  be 
promptly  cooled,  placed  in  sterile  bottles  and  stored  at  50  de- 
grees F.  or  lower  until  delivered  (Fig.  59). 

(i)  A  bacterial  count  not  in  excess  of  10,000  per  c.c.  is  per- 
mitted and  the  milk  must  not  be  over  24  hours  old  when 
delivered. 

Certified  milk  represents  the  highest  grade  of  milk  obtainable. 
Its  careful  production  makes  it  well  adapted  to  infant  feeding. 


PRODUCTION   AND    INSPECTION    OF    MILK 


159 


Fig.  56. — Bottling  room  in  a  high-class  city  dairy.  Milk  is  cooled  by  flowing 
over  the  corrugated  cooler  in  the  center  of  the  illustration,  after  which  it  flows 
into  the  tank  of  the  bottling  machine  below.      (Bull.  56,  Hygienic  Laboratory.) 


■■■H 


Fig.  57. — Loew  hydro-pressure  bottle  washer.  Installed  in  Meyer  Sanitary 
Milk  Co.,  Kansas  City,  Kansas.  A  machine  for  the  washing  and  wrinsing  of 
milk  bottles.      (Loew  Mfg.  Co.,  Cleveland,  O.) 


i6o 


PRACTICAL   PREVENTIVE    MEDICINE 


The  term  inspected  milk  is  applied  to  a  very  good  grade  of 
raw  milk,  however  not  as  reliable  as  the  certified  grade.  It  is 
applied  to  clean,  fresh  milk  from  healthy  cows  which  are  tuber- 
culin tested  and  examined  by  a  veterinarian.  The  cows  are 
fed,  watered,  housed  and  milked  under  good  conditions,  but 
not   necessarily   equal   to    those   required   for   certified   milk. 


ao' 


•30' 
Time  (Mmutesj. 


+0' 


■50', 


Dr.  CC.Nort/, 


Fig.  58. — Showing  the  time  and  temperature  necessary  for  the  destruction  of 
infective  agents  in  milk,  with  the  effect  of  heat  on  the  constituents  of  milk. 
(Dr.  C.  E.  North,  N.  Y.  City.) 

Scrupulous  cleanliness  must  be  used  in  milking  and  care  taken 
to  prevent  persons  having  communicable  disease  coming  in  con- 
tact with  the  milk.  It  should  be  placed  in  sterile  bottles  and 
stored  at  50  degrees  F.  A  bacterial  count  of  not  over  100,000 
bacteria  per  c.c.  is  permissible. 

The  term  market  milk  is  applied  to  all  milk  not  certified  or 
inspected  in  accordance  with  the  above  definitions,  and  to  all 


PRODUCTION  AND   INSPECTION   OF   MILK 


161 


milk  of  unknown  origin.     Common  sense  indicates  the  neces- 
sity for  the  pasteurization  of  all  milk  of  this  grade. 

5.  Dairy  Inspection. — ImprovemeDt  in  the  hygienic  quality 
of  milk  can  best  be  accomplished  by  supervision  of  the  condi- 
tions under  which  milk  is  produced  and  handled.  Results  are 
accomplished  along  two  lines  (1)  by  the  enforcement  of  regula- 
tions designed  to  secure  proper  conditions  and  methods,  and 


Fig.   59. — A  vat  pasteurizer  suitable  for  the  pasteurization  of  milk  by  the 
holding  process.     (Miller  Pasteurizing  Machine  Co.,  Canton,  O.) 

(2)  the  education  of  dairymen  along  the  lines  of  hygienic 
milk  production.  There  can  be  no  doubt  that  markedly  bene- 
ficial results  follow  the  introduction  of  efficient  systems  of  in- 
spection by  tactful  inspectors.  On  the  other  hand,  inspection 
will  not  cure  all  of  the  evils  or  absolutely  safeguard  the  milk 
supply.  Inspection  requires  that  all  sources  of  supply  be 
examined,  hence  in  order  that  they  may  be  known  to  the 
authorities  a  system  of  liscensure  is  necessary.  Inspections  are 
11 


162 


PRACTICAL   PREVENTIVE    MEDICINE 


of  the  greatest  value  when  a  fixed  routine  is  followed  in  making 
the  inspections.     To  this  end  score  cards  are  of  great  value. 


;ooung 


PAST€URtZ!NG 


"E-HEATlNa 


Pig.  60. — A  large  type  of  pasteurizing  machine,  for  in-bottle  pasteurizing. 
Capacity  5000  pint  bottles  per  hour.  (Barry-Wehrniller  Machinery  Co.,  St. 
Louis,  Mo.) 


Fig.  61. — Loew  in-the-bottle  pasteurizer.  Installed  by  Meyer  Sanitary  Milk 
Co.,  Kansas  City,  Kansas.  Another  type  of  in-bottle  pasteurizer.  The  milk 
is  heated  by  jets  of  hot-water.      {Loew  Mfg.  Co.,  Cleveland,  0.) 

Score  cards  are  constructed  on  a  percentage  basis,    different 
values  being  assigned  to  different  phases  of  the  subject;  equip- 


PRODUCTION   AND   INSPECTION    OF   MILK  163 


UNITED  STATES   DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ANIMAL  INDUSTRY, 

DAIRY  DIVISION. 


SANITARY  INSPECTION  OF  DAIRY  FARMS. 


SCORE    CARD. 

Indorsed  by  the  Official  Dairy  Instructors'  Association. 

Owner  or  lessee  of  farm ■_ , 

P.  O.  address State 

Total  number  of  cows Number  milking , 

Gallons  of  milk  produced  daily 

Product  is  sold  by  producer  in  families,  hotels,  restaurants,  stores, 

to  — dealer. 

For  milk  supply  of. , 

Permit  No ..—  Date  of  inspection ....,  191 

Remarks: 


_  _  „  Inspector^ 

D.  ».  316.—  5-S-15— 5,000.  8—1763 

Pig.  62. 


164 


PRACTICAL    PREVENTIVE    MEDICINE 


EQUIPMENT 


cows. 

Health. 

Apparently  in  good  hoalth 1 

If  tested  with  tuberculin  within 
a  year  and  no  tuberculosis  is 
found,  or  if  tested  within  six  . 
months  and  all  reacting  ani- 
mals removed 5 

(If  tested  within  a  year  and  react- 
ing animals  are  found  and  removed, 
3) 

Food  (clean  and  wholesome) 

Water  (clean  and  fresh) ........ 

BTABLIS. 

Location  of  stable.. .............. 

Well  drained i  1 

Free   from   contaminating   sur- 
roundings   .X. 

Construction  of  stable 

Tight,  sound  floor  and  proper 

gutter ..  2 

Smooth,  tighc  walls  and  ceiling.  1 

Proper  stall,  tie,  and  manger 1 

Provision  for  light:  Four  sq.  ft.  of 

glass  per  cow 1. 

(Three  sq.  ft.,  3,  2  sq.  ft.,  2;  1  sq. 
ft.,  I.  Deduct  for  uneven  diBtribu- 
tion.) 

Iledding ....... 

Ventilation . 

Provision  for  fresh  air,  control- 
lable flue  system ^ 3 

(Windows  hinged  at  bottom, 
1.5;      sliding     windows,    1; 
other  openings,  0.5.) 
Cubic  feet  of  space  per  cow,  600 

ft 3 

(Less  than  600  ft.,  2;  less  than 
400  ft.,  1;  less  than  300  ft.,  0.) 
Provision  for  controlling   tem- 
perature.........™..  ...  1 

TJTENBIL8. 

Construction  and  condition  of  uten- 
sils  . .: 

Water  for  cleaning 

(Clean,  convenieut,  and  abundant.) 

8mall-top  milking  pail 

Milk  cooler .... 

Clean  milking  suits 

MILK   BOOM  OE  MILK   HOUSE. 

Location:  Free  from  contaminating 
surroundings 

Construction  of  milk  room 

Floor,  walls,  and  ceiling 1 

Light,  ventilation,  screens 1 

[Separate  rooms  for  washing  utensils 
and  handling  milk 

facilities  for  steam 

(Hot  water,  0.5.) 

Total 


SCORE. 


Perfect.    Allowed. 


METHODS. 


Clean 

(Free  from  visible  dirt,  6.) 

STABLES. 

Cleanliness  of  staWcs. . ... 

Floor ; ... -_     .2 

Walls .' I 1 

Ceiling  and  ledges ...  1 

Mangers  and  partitions 1 

Windows 1 

Stable  air  at  milking  time ... 

Freedom  from  dust 3 

Freedom  from  odors 2 

Cleanliness  of  bedding 

Barnyard . 

Clean ... I 

Well  drained I 

Eemoval  of  manure  daily  to  60  feet 
from  stable- '. 

MILK  BOOM  0B  MILE  HOUSE. 

Cleanliness  of  milk  room. 

UTENSILS  AND   MILKINO. 

Care  and  cleanliness  of  utensils 

Thoroughly  washed 2 

Sterilized  insteam'for  15  min- 
utes   3 

(Placed  over  steam  jet,  or  scalded 

with  boiling  water,  2.) 

Protected  from  contamination.  3 

Cleanliness  of  milking , 

Clean,  dry  hands 3 

Udders  washed  and  wiped :_  6 

(Udders  cleaned  with  moist  cloth, 

4;  cleaned  with  dry  cloth  or  brush 

a  t  least  15  minutes  before  milking, 

1-) 

HANDLING  THE  MILE. 

Cleanliness  of  attendants  in  milk 
room 

Milk  removed  immediately  from 
stable  without  pouring  from  pail.. 

Cooled  immediately  after  milking 
each  cow 

Cooled  below  50°  F 

(51°  to  55°,  4;  56°  to  00°,  2.) 

Stored  below  60°  F 

(51°  to  55°,  2;  56°  to  60°,  1.) 

Transportation  below  50°  F 

f51°  to  55°,  1.5;  66°  to  60°,  1.) 
(If  delivered  twice  a  day,  allow 

perfect  score  :&I  storage  and  trans- 
portation.) 


SCORE 


Perfect.    Allowed. 


Equipment- +  Methods , 


Final  Score. 


Note  1. — If  any  exceptionally  filthy  conditijD  is  found,  particularly  dirty  utensils,  the  total  score  may  be  fur- 
ther limited. 

Note  2. — If  the  water  is  exposed  to  dangerous  contamination,  or  there  is  evidence  of  the  presence  of  a  dangerou3 
disease  in  aDimals  or  attendants,  the  score  shall  be  0.  8 — 1763 


Pig.  62. —  (Continued.) 


PRODUCTION   AND    INSPECTION    OF   MILK  1 65 

merit  and  methods  (Fig.  62).  If  perfect,  a  100  score  would  be 
allowed,  but  suitable  deductions  are  made  for  the  observed 
deficiencies.  The  method  permits  of  the  tairest  comparison  of 
different  dairies  and  permits  the  dairyman  to  understand  the 
deficiencies  of  his  equipment  and  methods.  Where  the  score 
cards  are  devised  upon  a  proper  basis,  i.e.,  emphasize  the  im- 
portant factors  in  the  production  of  a  safe  milk  and  ignore  or 
minimize  the  trivial  features,  excellent  results  will  follow. 
It  is  physically  impossible,  however,  to  secure  a  sufficient  staff 
of  inspectors  to  insure  the  freedom  of  a  milk  supply  from  infec- 
tion at  all  times.  Inspection  is  of  value  in  the  investigation  of 
supposed  milk  born  outbreaks  and  doubtless  prevents  many, 
but  it  is  not  an  absolute  safeguard. 

6.  The  Care  of  Milk  in  the  Home. — Proper  care  of  milk 
in  the  home  is  of  fundamental  importance  when  employed  in 
infant  feeding,  though  less  so  in  the  case  of  adults.  Its  im- 
portance will  be  brought  out  later.  For  the  present  we  will  only 
consider  what  constitutes  proper  care.  In  the  main  this  con- 
sists in  maintaining  proper  conditions  of  storage,  so  that  the 
milk  is  kept  chilled  until  it  is  entirely  consumed.  In  the  homes 
of  the  well-to-do,  where  refrigerators  and  a  constant  supply  of 
ice  are  available,  this  is  no  problem.  On  the  other  hand  in  the 
homes  of  the  poor  where  refrigerators  are  not  available,  a  little 
ingenuity,  together  with  a  regular  supply  of  ice  will  meet  all 
requirements.  A  very  simple  home  made  milk  refrigerator  is 
described  in  Public  Health  Bulletin  No.  102  of  the  Public 
Health  Service. 

It  may  also  be  advisable  or  necessary  to  pasteurize  milk  in 
the  home,  either  as  a  routine  or  as  an  emergency  procedure. 
Of  course  doubtful  milk  can  be  rendered  safe  by  boiling,  though 
few  people  find  the  taste  of  boiled  milk  palatable.  Home 
pasteurization  should  be  practised  where  cows  milk  is  required 
for  infant  feeding  and  where  the  only  milk  available  is  of  the 
inspected  or  market  grades.  Since  the  principles  of  pasteuriza- 
tion have  already  been  explained  it  is  not  necessary  to  describe 
their  adaption  to  this  purpose,  since  ingenuity  can  readily  adapt 
the  process  to  local  home  facilities.  (See  circ.  197  Bureau 
Animal  Industry,  U.  S.  Dept  of  Agriculture). 

REFERENCES 

A  Home  Made  Milk  Refrigerator.  Public  Health  Bull.  102,  U.  S.  P.  H.  S. 
The  Four  Essential  Factors  in  the  production  of  Milk  of  Low  Bacterial 
Count.     Bull.  642,  U.  S.  Dept.  of  Agriculture. 


l66  PRACTICAL  PREVENTIVE  MEDICINE 

Directions  of  the  -Home  Pasteurization  of  Milk.     Circ.  197  for  Bureau  Animal 

Industry.     U.  S.  Dept.  Agriculture. 
A  Simple   Steam  Sterilizer  for  Farm   and  Dairy  Use.     Farmers   Bull.  748. 

U.  S.  Dept.  Agriculture. 
Dirt   Sediment   Testing,   a   factor   in   obtaining  clean  milk.     Reprint  Series 

No.  15,  Health  Department.     New  York  City. 
The  Modern  Milk  Pail.     Bull.  326,  New  York  Agr.  Expt.  Sta.,  Geneva,  N.  Y. 
A  Guide  for  Formulating  a  Milk  Ordinance.     Bull.  585,  U.  S.  Dept.  Agr. 
Production  and  Inspection  of  Milk.     Spec.  Bull.  Hawaii  Agr.  Expt.  Sta. 
Milk  and  its  Relation  to  the  Public  Health.     Bull.  56,  Hyg.  Lab.,  U.  S.  P  H.  S. 
Medical  Milk  Commisions  and  Certified  Milk.,  Bull.  104,  Bureau  of  Animal 

Industry,  U.  S.  Dept.  of  Agriculture. 
Score  Card  System  of  Dairy  Inspection.  Circ.  199,  Bur.  An.  Ind.  U.  S.  De- 
partment of  Agrictulture. 
Pasteurization  of  Milk  in  Bottles  and  Bottling  Hot  Milk  Pasteurized  in  Bulk. 

Bull.  240,  U.  S.  Dept.  of  Agriculture. 
The  Thermal   Death  Points  of  Pathogenic  Micro-organisms  in  Milk.     Bull. 

42,  Hygienic  Lab.  U.  S.  P.  H.  S. 
Pasteurization  of  Milk.  Circ.  184,  Bur.  An.  Ind.,  U.  S.  Dept.  Agr. 
Standard   Methods  for   the  Bacteriological  Analysis   of   Milk.     Am.  Public 

Health  Ass'n. 
History,  Development  and  Statistics  of  Milk  Charities  in  the  United  States. 

Reprint  50,  Public  Health  Reports. 


CHAPTER  XVIII 
MILK  AS  A  ROUTE  OF  INFECTION 

1.  Milk  as  a  Medium  for  Bacteria. — In  this  connection  it  is 
necessary  to  call  attention  to  a  phenomenon  observed  in  milk 
which  is  commonly  referred  to  as  the  "germicidal"  property. 
In  the  first  few  hours  after  milk  is  withdrawn  from  the  cow 
there  is  a  transitory  reduction  in  the  number  of  colonies  which 
develope  on  plates  poured  from  unit  volumes  of  milk,  as  com- 
pared with  the  number  originally  present.  In  a  few  hours 
the  numbers  show  no  furtner  reduction,  commence  to  in- 
crease and  soon  greatly  exceed  those  originally  present.  This 
phenomenon  is  not  apparent  in  milk  which  has  been  heated  to 
50    degrees    C.  .  Several    explanations    have    been    advanced. 

(a)  Some  consider  this  phenomenon  as  a  manifestation  of  a 
true  germicidal  property  in  milk  and  that  the  temporary  diminu- 
tion is  due  to  a  partial  destruction  of  the  bacteria  originally 
introduced. 

(b)  Or  it  may  be  due  to  an  inhibition  of  those  species  which 
find  milk  an  unfavorable  environment  for  development. 

(c)  Others  consider  the  phenomenon  is  due  to  the  action  of 
agglutination,  i.e.,  the  reduction  in  colonies  is  due  to  the  clump- 
ing of  bacteria  and  that  their  numbers  are  not  actually  reduced. 
This  view  is  strengthened  by  the  influence  of  heating  as  already 
noted. 

2.  Sources  of  Pathogenic  Organisms  which  may  be  En- 
countered in  Milk.- — First  let  us  consider  organisms  derived 
from  the  producing  animals: 

(a)  Cows. 

1.  The  mammary  gland. 
Mycobacterium  tuberculosis. 
Virus  of  foot  and  mouth  disease. 
Bacillus  anthracis. 

Virus  of  cow  pox. 
Streptococci. 

2.  From  fecal  contamination. 
Mycobacterium  tuberculosis. 
Bacterium  enteritidis 

167 


1 68  PRACTICAL   PREVENTIVE    MEDICINE 

(b)  Goats, 
i.  The  mammary  gland. 

Bacterium  melitensis.     (Malta  fever). 

Equally  important  are  infective  agents  derived  from  human 
sources,  thus: 

i.  Fecal  and  urinary  discharges. 
Bacterium  typhosus. 

Various  non-specific  organisms  producing  diarrhea. 
2.  Nasopharyngeal  secretions. 
Mycobacterium  diphtheria. 
Virus  of  scarlet  fever. 
Streptococcus  hcemolyticus.     (Septic  sore  throat). 

3.  Development  of  Pathogenic  Bacteria  in  Milk. — All  of 
the  rapidly  growing  pathogenic  bacteria  find  milk  a  very 
favorable  medium,  consequently  their  numbers  will  increase. 
Thus  individuals  consuming  contaminated  milk  will  ingest 
large  numbers  of  the  organisms,  in  other  words,  the  dosage  of 
infection  will  be  great.  The  extent  to  which  multiplication 
takes  place  is. modified  by  a  number  of  factors  among  which 
may  be  mentioned  the  following:  Germicidal  property,  tempera- 
ture of  storage,  age  of  the  milk  and  the  time  at  which  the  in- 
fective agents  gain  introduction.  Of  these  temperature  is  one 
of  the  most  important.  The  nearer  the  temperature  of  storage 
approaches  body  heat  the  greater  will  be  the  development  of 
pathogenic  organisms. 

The  incidence  of  milk-borne  disease  in  a  given  population 
is  greatest  among  those  who  use  milk  as  a  beverage.  A  lighter 
incidence  will  be  found  among  those  who  only  employ  milk 
on  cereals,  or  as  a  diluent  in  tea,  coffee  or  cocoa.  Since  women 
and  children  are  usually  the  heaviest  milk  drinkers,  the  heaviest 
evidence  of  milk-borne  disease  is  found  in  these  age  and  sex 
groups.  As  we  have  seen,  bacterial  multiplication  in  milk  is 
directly  proportionate  to  the  external  temperature,  conse- 
quently the  dosage  of  infection  in  a  given  sample  of  infected 
milk  will  be  greater  in  warm  weather.  As  a  rule  milk-borne 
epidemics  occur  during  the  warmer  seasons  of  the  year,  or  follow- 
ing periods  of  warm  weather  in  winter.  The  large  dosage  of 
infective  agents  received  reduces  the  incubation  period  to  its 
lower  limits,  but  peculiarly,  in  the  case  of  typhoid  at  least,  the 
disease  when  milk  borne  is  commonly  milder  than  usual.  In 
the  care  of  typhoid  and  diphtheria  transmission  by  milk  it  will 
be  found  that  the  contamination  of  the  milk  with  these  organ- 


MILK   AS    A   ROUTE    OF   INFECTION  1 69 

isms  has  been  intermittent,  frequently  only  a  single  lot  being 
infected.  Investigation  will  reveal  the  dairy  or  distributing 
agency  responsible  and  the  distribution  of  the  cases  will  be 
found  to  coincide  with  the  distribution  of  that  supply.  The 
possibilities  in  the  contamination  of  milk  and  the  range  of  its 
distribution  are  indicated  in  Fig.  64. 

4.  Bovine  Tuberculosis  in  Man. — In  the  past  widely  diver- 
gent views  have  been  entertained,  from  the  belief  that  the 
bovine  strain  never  affected  man  to  the  opposite  view,  that  all 
human  infection  was  derived  from  bovine  sources.  Such 
widely  divergent  views  naturally  stimulated  research  and  as  a 
consequence  it  is  now  possible  to  say  with  some  degree  of  finality 
that  the  bovine  tubercle  bacillus  is  responsible  for  from  10 
to  15  per  cent,  of  all  human  tuberculosis,  the  clinical  types 
produced  being  chiefly  cervical  adenitis,  abdominal  tuberculosis 
and  generalized  tuberculosis  of  alimentary  origin.  It  is  exceed- 
ingly rare  in  pulmonary  tuberculosis,  which  is  practically  due 
only  to  the  human  strain  of  the  tubercle  bacillus.  Infection 
is  usually  found  in  children  under  sixteen  years  of  age,  while 
susceptibility  is   greatest   during   the   first  five  years  of  life. 

In  New  York  City  7  per  cent,  of  the  deaths  among  those 
of  less  than  five  years  of  age  are  due  to  bovine  tuberculosis. 
Infection  is  contracted  through  the  consumption  of  contami- 
nated milk.  When  we  consider  the  wide  prevalence  of  the 
disease  in  cattle,  as  indicated  by  the  following  table  and  the 
small  proportion  of  human  infection,  one  must  conclude  that 
human  infection  is  not  very  easy. 

The  bovine  tubercle  bacillus  has  been  found  in  the  following 
proportions  in  the  milk  supply  of  different  cities: 

New  York  City 16  per  cent,  of  milk 

specimens  examined. 

Washington  City 2.7-6.7  per  cent,  of  milk 

specimens  examined. 

Chicago 7.9  per  cent,  of  milk 

specimens  examined. 

Manchester,  England 8.9  per  cent,  of  milk 

specimens  examined. 

Tuberculosis  is  widespread  among  the  dairy  herds  of  the 
United  States,  though  by  constant  effort,  reduction  is  being 
gradually  accomplished.  A  few  years  ago  it  was  found  that 
302  of  421  dairy  herds  examined  in  the  state  of  New  York 
were  infected.  It  has  been  authoritatively  estimated  that  30 
per  cent,  of  all  dairy  herds  in  the  U.  S.  are  infected. 


170  PRACTICAL   PREVENTIVE    MEDICINE 

The  presence  of  tubercle  bacilli  in  milk  usually  arises  as  a 
result  of  milk  contamination  with  bovine  feces.  Mammary- 
tuberculosis  is  very  rare  in  cattle,  only  from  1  to  10  ten  cent, 
of  infected  cattle  having  a  tuberculous  mastitis.  On  the  other 
hand,  pulmonary  involvement  is  most  common.  The  sputum 
instead  of  being  expectorated  is  swallowed  and  the  organisms 
pass  out  of  the  body  with  the  feces. 

Since  the  disease  is  chronic  and  the  infection  commonly 
widespread  in  invaded  herds,  it  is  easy  to  understand  that  the 
contamination  of  the  milk  from  an  infected  dairy  will  probably 
be  continuous.  On  the  other  hand,  the  tubercle  bacillus  is 
very  slow  growing,  so  that  in  the  interval  between  production 
and  consumption  of  the  milk  no  appreciable  increase  in  the 
number  of  organisms  will  take  place. 

Pasteurization  of  milk  at  a  temperature  of  at  least  6o°C. 
is  the  only  safeguard  against  milk-borne  tuberculosis.  Further- 
more pasteurization  should  be  in  closed  vessels  to  avoid  the 
formation  of  the  scum  upon  the  surface  of  the  milk  which 
serves  to  insulate  some  of  the  organisms  from  the  heat. 

The  tuberculin  testing  of  dairy  cattle  and  the  slaughtering 
of  those  found  to  react  is  a  very  satisfactory  means  of  eradicat- 
ing the  disease  and  has  been  successfully  practiced  for  some 
time.  This  method,  however,  gives  rise  to  serious  losses  in  the 
case  of  blooded  stock.  To  overcome  this  disadvantage  the 
Bang  system  was  originated.  Reacting  cows  without  open, 
lesions  are  not  killed,  but  are  permitted  to  be  bred.  Following 
calving  the  calves  are  immediately  separated  from  their  mothers 
and  never  permitted  to  suckle.  The  cows  are  milked  and  the 
milk  pasteurized  before  being  fed  to  the  calves.  Of  course  the 
reacting  cows  used  for  breeding  are  separated  from  all  other 
healthy  cattle.  The  success  of  this  method  lies  in  the  fact  that 
intra-uterine  infection  is  so  rare  as  to  be  a  negligible  factor  in 
the  dissemination  of  the  disease.  As  a  consequence,  the  desir- 
able qualities  of  highly  bred  cattle  may  be  perpetuated  and  the 
losses  are  very  much  diminished,  while  healthy  uninfected 
progeny  are  secured,  and  in  the  course  of  a  few  years  a  farm  is 
clear  of  tuberculosis. 

5.  Milk-borne  Typhoid  Fever. — Since  milk-borne  typhoid 
fever  was  first  recognized  in  1857,  over  three  hundred  similar 
outbreaks  have  been  reported  in  the  literature  and  this  must 
represent  a  minor  fraction  of  the  total. 

Milk-borne  typhoid  is  urban  rather  than  rural  in  character 
and  is  probably  responsible  for  a  considerable  proportion  of 


MILK   AS   A   ROUTE    OF    INFECTION 


171 


endemic  typhoid,  represented  chiefly  as  small  epidemics. 
Ogan  estimates  that  39  per  cent,  of  all  typhoid  fever  in  New 
York  City  is  milk-borne.  In  Washington  City  the  minimum 
number  of  milk  cases  represent  from  9  per  cent,  to  n  per  cent, 
of  all  typhoid,  these  cases  occurring  chiefly  in  small  epidemics. 
An  interesting  bit  of  data  in  this  connection  is  the  following 
observation  from  Washington. 

TABLE  VIII 


Year 

Pasteurization 

Cases  on  milk  routes  per  ioo 

,000  gallons 

Dealer  3 

Dealer  4 

Dealer  8 

1906 

none 

16.6 

52.5** 

36.6 

1907 

none 

7-i 

21.6 

17. 1 

1908 

yes 

5-8 

10. 1 

18.8  * 

1909 

yes 

1.4 

7.0 

6.9 

**  A  pronounced  milk  outbreak. 
*  Not  pasteurized  until  1909. 


These  figures  clearly  indicate  that  milk  is  a  considerable  factor 
in  endemic  typhoid,  and  demonstrates  the  protective  value  of 
pasteurization. 

In  considering  the  introduction  of  the  typhoid  bacilli  into  the 
milk  let  us  separately  consider  the  dairy  and  the  retail  end. 

Infection  of  the  milk  at  the  dairy  or  producing  farm  has  been 
observed  to  have  resulted  from  the  following  practices  or  cir- 
cumstances in  different  epidemics  (Fig.  64) : 

(a)  Unrecognized  cases  serving  as  milkers  or  handlers. 

(b)  The  nurse  of  a  typhoid  patient  serving  as  a  milker  or 
milk  handler  (Fig.  63). 

(c)  Washing  milk  utensils  in  contaminated  water. 

(d)  Washing  milk,  utensils  with  the  same  dish  cloths  used  for 
dishes  of  a  typhoid  case. 

(e)  Adulteration  of  milk  with  infected  water. 

From  the  standpoint  of  the  distribution  of  a  milk  supply, 
the  following  circumstances  have  given  rise  to  epidemics: 

(a)  Unrecognized  cases  or  carriers  delivering  milk  or  working 
in  milk  depots. 

(b)  Use  of  bottles  from  premises  on  which  typhoid  cases 
existed  without  their  previous  sterilization. 

The  development  of  the  typhoid  bacillus  in  milk  is  rapid  as 


172 


PRACTICAL    PREVENTIVE    MEDICINE 


A  LOCALIZED    EPIDEMIC    OP  TYPHOID   PEiVER 
DOE:    TO    AN   INFECTED    MILK.  SUPPLY 


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EDUCATIONAL   £ERIE5-No15 


Fig.  63. 


MILK    AS    A    ROUTE    OF    INFECTION 


173 


the  temperature  rises  above  ten  degrees  C.  As  a  consequence 
most  milk  outbreaks  occur  during  the  summer  months  or  during 
warm  periods  in  winter.  The  outbreaks  are  explosive  in  char- 
acter and  affect  milk  drinkers  most  heavily,  particularly  women 


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z 


INFECTED 
WATER 


INFECTED 
FLIES 


INFECTED 
MILK    UTENSILS 


INFECTED  EMPLOYEES 
INFECTED    BOTTLES 


INFECTION   IN  CONSUMERS 
HOME 


[Qp-T-A  II     I — INFECTED   EMPLOYEES 

5JOR1 


Fig.  64. — The  distribution  of  infection  by  milk. 


and  children.  The  introduction  of  the  infective  agent  is  inter- 
mittent and  as  a  result  several  explosive  crops  of  cases  may  be 
observed. 

6.  Other  Milk-Borne  Infections. — The  distribution  of  scarlet 
fever,  diphtheria  or  septic  sore  throat  by  milk  does  not  essen- 


I  y4  PRACTICAL    PREVENTIVE    MEDICINE 

tially  differ  from  that  of  typhoid  fever,  although  they  are  of  rarer 
occurrence. 

7.  Other  Milk  Products  as  Routes  of  Infection. — Dairy 
products,  as  well  as  fresh  milk  may  serve  to  distribute  infective 
agents.  Thus  the  cream  supply,  ice  cream,  butter  and  butter 
milk  must  be  borne  in  mind  in  the  investigation  of  epidemics. 

REFERENCES 

Milk  and  its  Relation  to  the   Public  Health.     Bulletin  56,  Hygienic  Labra 

tory.     U.  S.  Public  Health  Service,  pp.  23-231;  455-525. 
Rosexatj:  Preventive  Medicine  and  Hygiene.     3rd,  Ed.  pp.  57i-579- 
Relationship   of    Milk    Supplies    to    Typhoid   Fever.     Reprint   380,   Public- 
Health  Reports. 


CHAPTER  XIX 
OTHER  FOOD  STUFFS  AS  ROUTES  OF  INFECTION 

We  will  now  give  a  brief  consideration  to  the  other  food-stuffs, 
exclusive  of  water  and  milk.  In  this  connection  it  is  apparent 
that  some,  such  as  meat,  may  serve  both  as  a  source  as  well  as 
a  route  of  infection. 

I.  Meat  as  a  Vehicle  of  Infection. — The  muscular  tissue  and 
certain  viscera  of  cattle,  sheep,  swine,  horses,  dogs,  and  goats 
are  largely  consumed  as  food  and  constitute  what  we  designate 
as  meat.  The  animals  slaughtered  for  this  purpose  may  be 
diseased,  in  which  event  their  meat  may  be  unsuited  for  food 
for  the  following  reasons: 

(a)  Infective  agents  to  which  man  is  susceptible  may  be 
present. 

(b)  The  meat  has  an  abnormal  appearance  and  hence  is 
repulsive. 

(c)  As  a  result  of  the  illness  the  food  value  of  the  meat  is 
lowered. 

Furthermore  careless  methods  of  slaughtering  may  result  in 
the  contamination  of  the  meat  with  micro-organisms  from  the 
intestinal  tract,  as  a  consequence  of  which  decomposition  takes 
place  more  rapidly. 

Danger  from  such  causes  may  be  eliminated  by  a  careful 
ante  mortem  inspection  of  the  animals  and  a  similar  inspection 
of  the  carcass  following  slaughter.  The  presence  of  diseased 
tissue  does  not  necessarily  justify  the  condemnation  of  the 
entire  carcass.  Condemnation  should  be  based  upon  an  accu- 
rate diagnosis  of  the  diseased  conditions  detected,  and  the  extent 
of  its  distribution.  Many  diseased  caracasses  can  be  safely  used 
in  part  as  food.  In  the  United  States  but  little  progress  in 
meat  inspection  has  been  made.  The  Federal  system  of  meat 
inspection  is  only  for  meats  designed  for  interstate  shipment 
and  export.  Meats  slaughtered  for  local  consumption  can 
only  be  supervised  by  local  authorities  and  very  little  has  been 
undertaken  in  this  direction. 

(a)  Diseases  of  animals  which  may  be  transmitted  through 
meat: 

175 


176  PRACTICAL  PREVENTIVE  MEDICINE 

i.  Meat  Poisoning. — By  this  term  is  meant  a  group  of  infec- 
tions and  intoxications  due  to  the  activity  of  several  different 
organisms.  The  conditions  are  all  highly  acute  and  occur  after 
a  very  brief  incubation  period,  so  that  clinically  they  do  not 
resemble  typical  infections.  Bacterially  we  find  the  organisms 
concerned  are  B.  enteritidis,  B.  proteus,  B.  paratyphosus  B.  and 
closely  related  forms,  and  also  B.  botulinus,  whose  action  is 
due  to  highly  potent  soluble  exotoxin.  These  outbreaks  have 
usually  been  associated  with  the  consumption  of  prepared  meat 
foods  (sausages,  etc.)  and  pork  has  been  the  meat  most  com- 
monly involved.  These  organisms  are  present  in  the  gastro- 
intestinal tract  of  the  domestic  animals  and  their  presence  in 
the  meat  is  probably  due  to  its  contamination  with  the  intes- 
tinal contents  and  feces  after  slaughter.  The  organisms  of  the 
enteritidis  group  are  all  killed  by  low  degrees  of  heating  (60 
degrees  for  30  min.),  but  they  possess  poisonous  endotoxins 
which  withstand  a  higher  temperature. 

2.  Verminous  Parasites. — Several  cestodes  and  one  nemotode 
are  of  considerable  importance,  the  latter  particularly.  The 
beef  tape  worm,  the  pork  tape  worm  and  the  fish  tape  worm  all 
pass  their  larval  stage  in  the  flesh  of  the  indicated  animal  and 
human  infection  with  all  is  primarily  derived  from  the  consump- 
tion of  parasitized  meat.  The  pork  tape  worm  possesses 
greater  importance  than  the  others,  since  an  individual  once 
infected  can  reinfect  himself,  as  man  can  also  serve  as  inter- 
mediate host.  The  most  important  parasite  is  the  nematode 
worm,  Trichinella  spiralis,  whose  larval  stage  is  commonly 
passed  in  swine.  Human  infection  is  derived  from  raw  pork. 
It  is  undoubtedly  the  most  common  and  the  most  important 
of  all  infections  derived  from  meat. 

3.  Other  Infections. — Tuberculosis,  anthrax,  rabies,  glanders, 
tetanus  and  foot  and  mouth  disease  are  all  diseases  of  the  food 
producing  animals,  transmissible  to  man,  yet  so  far  as  we  know, 
no  cases  are  on  record  where  human  infection  was  contracted 
from  the  consumption  of  infected  meat.  Man  is  susceptible  to 
all  of  these,  but  his  infection  is  derived  from  different  routes 
than  meat. 

3.  Shell  Fish  as  a  Vehicle  of  Infection. — Oysters,  clams, 
cockels  or  mussels  are  frequently  secured  from  beds  in  bays, 
inlets,  etc.,  that  are  contaminated  by  the  sewage  of  large  com- 
munities, or  else  floated  in  brackish  water  similarily  contami- 
nated (Figs.  65,  66).  Thus  opportunities  are  afforded  for  the 
shell   fish  to  become  contaminated  with  infective  agents  de- 


OTHER    FOOD    STUFFS    AS    ROUTES    OF    INFECTION 


177 


rived  from  human  excreta.     A  considerable  number  of  typhoid 
epidemics  have  been  ascertained  to  have  been  caused  by  the 


t.-*i*i%!t"%iA 


Fig.  65. — Two  oyster  floats  anchored  in  the  rear  of  oyster  houses.  Privy 
vaults  are  located  in  the  rear  of  these  buildings,  refuse  being  dumped  directly 
into  the  river.  It  is  a  crime  punishable  by  $100  fine  to  float  oysters  in  this 
river.  An  epidemic  of  typhoid  occurred  some  years  ago  from  oysters  floated 
in  this  place.     {Bull.  136,  Bur.  Chemistry.) 


Fig.  66. — A  closer  view  of  the  upper  oyster  floats  shown  in  Fig.  65.  Note 
the  pile  of  oysters  in  the  float.  Picture  taken  at  low  tide;  about  two  hours  later 
these  same  oysters  were  found  in  the  adjoining  oyster  house  ready  for  sale. 
Oysters  drink  best  at  the  beginning  of  flood  tide  and  are  "plumpest"  about  one 
or  two  hours  afterwards.  The  main  sewer  of  the  city  empties  under  the  bridge 
above.      {Bull.  136,  Bur.  Chemistry.) 


consumption  of  sewage  contaminated  oysters  and  clams.     These 
observations  have  chiefly  been  made  in  England.     The  typhoid 


12 


178  PRACTICAL    PREVENTIVE    MEDICINE 

bacillus  will  survive  in  oysters  for  as  long  as  six  weeks,  and  as 
changes  of  decomposition  set  in,  will  increase  in  numbers. 

4.  Cooked  and  Canned  Foods. — For  the  most  part  hygienists 
have  looked  upon  cooking  as  a  process  of  distinct  hygienic 
value,  entirely  apart  from  its  influence  upon  the  digestibility 
of  food,  for  the  application  of  heat  will  have  a  distinctly  dis- 
infecting action.  However  it  now  appears  that  not  all  cooking 
operations  can  be  considered  sufficiently  thorough  to  altogether 
eliminate  danger  in  cooked  foods. 

The  greatest  danger  appears  to  exist  where  large  lots  of 
food  are  cooked  at  one  time,  for  here  the  bulk  of  the  material 
is  so  great  that  the  interior  is  insufficiently  heated  and  hence 
not  sterilized.  Furthermore  bacterial  spores  can  survive  cook- 
ing or  the  canning  process.  Little  positive  epidemiological 
evidence  is  at  present  available  concerning  food  as  a  route  of 
infection. 

Baked  Spaghetti:  An  extensive  outbreak  of  typhoid  has  been 
observed  in  California  in  which  infection  was  derived  from  the 
consumption  of  a  large  dish  of  baked  spaghetti  prepared  by  a 
typhoid  carrier.  Experimentally  it  was  found  that  in  baking 
such  a  large  dish  that  the  typhoid  bacillus  could  survive  even 
though  the  exterior  was  charred. 

Fried  Fish:  Several  outbreaks  of  typhoid  fever  in  London 
appeared  to  be  due  to  the  consumption  of  fried  fish  secured 
from  sewage  contaminated  waters. 

Botulism:  Recently  considerable  evidence  has  been  brought 
forward  from  the  Pacific  coast  to  the  effect  that  the  spores  of 
B.  botulinus  can  survive  the  process  or  canning.  Several  out- 
breaks of  botulism  due  to  the  consumption  of  home  canned 
vegetables  have  been  reported.  Outside  of  this  area  botulism 
is  practically  unknown  in  this  country.  The  European  out- 
breaks have  occurred  in  connection  with  the  consumption  of  pork 
sausage. 

On  the  other  hand,  commercially  canned  foods  have  not  until 
recently  been  implicated  in  botulinus  intoxication.  A  few  in- 
stances of  cans  of  contaminated  ripe  olives  which  caused  epidem- 
ics, have  been  noted.  It  would  appear  that  commercially 
canned  food  from  cans  that  are  not  obviously  spoiled  (swollen, 
leaky)  are  as  safe  as  any  foods  available. 

5.  Fresh  Vegetables. — A  few  outbreaks  of  typhoid  have 
occured  as  the  result  of  the  consumption  of  raw  fresh  vegetables 
grown  in  gardens  heavily  manured  with  human  excreta.     In  this 


OTHER    FOOD    STUFFS    AS    ROUTES    OF    INFECTION  1 79 

connection  celery,  lettuce,  radishes  and  watercress  have  been 
incriminated. 

REFERENCES 

Rosenau:  Preventive   Medicine   and    Hygiene.     3rd    Ed.,    pp.    605-643. 

Chapin:  Sources  and  Modes  of  Infection.     Chap.  VII,  pp.  266. 

Shell   Fish   Contamination  from    Sewage   Polluted   Waters   and  from  other 

Sources.     Bull.  136,  Bur.  Chemistry.     W.  S.  Dept.  Agriculture. 
Vegetable  as  a  possible  factor  in   the  dissemination  of  typhoid  fever.     Re- 
print 82,  Public  Health  Reports. 


CHAPTER  XX 
INSECTS  AS  VECTORS  OF  INFECTIVE  AGENTS 

Two  types  of  the  insect  transmission  of  infective  agents  are 
discernable,  namely  biological  and  mechanical. 

i .  Biological  Transmission. — In  this  group  transmission  of  the 
infective  agent  is  accomplished  by  the  aid  of  some  blood  sucking 
arthropod  in  whose  body  certain  definite  stages  of  the  infective 
agents'  life  cycle  are  passed.  So  far  as  known  the  infective 
agents  transmitted  by  this  means  have  no  other  means  of 
transmission. 

Biological  transmission  of  the  parasites  producing  the  follow- 
ing diseases  is  certain,  namely;  Malaria,  Yellow  Fever,  Sleeping 
Sickness,  Rocky  Mountain  Spotted  Fever,  Chagas'  disease, 
Relapsing  Fever,  Typhus  Fever,  and  Kala  Azar.  It  is  prob- 
ably the  usual  means  of  transmission  of  Filiariasis  and  Dengue. 
The  parasites  concerned  in  this  method  of  transmission  are  quite 
diverse,  though  apparently  all  belong  to  the  animal  kingdom. 
Thus  we  have  protozoa,  filterable  viruses  and  nematodes.  The 
groups  of  arthropods  concerned  are  also  quite  diverse,  although 
they  all  have  the  common  habit  of  sucking  blood,  as  for  example; 
mosquitoes,  biting  flies,  biting  bugs,  ticks,  and  lice.  These 
arthropods  are  either  temporary  or  permanent  ectoparasites  of 
mammals,  living  a  life  more  or  less  intimately  connected  with 
the  mammalian  species  upon  which  they  prey. 

The  infective  agents  concerned  undergo  oniy  an  asexual 
multiplication  in  their  vertebrate  host,  hence  the  vertebrate  is 
known  as  the  intermediate  host.  On  the  other  hand,  sexual 
development  takes  place  in  the  arthropod  which  is  known  as 
the  definitive  host.  The  relation  of  the  infective  agents  to  the 
arthropod  species  concerned  in  their  transmission  is  usually 
specific  or  nearly  so.  Where  not  specific  we  find  that  only 
closely  allied  species  of  arthropods  are  involved.  Similarly 
we  may  find  a  high  degree  of  specificity  on  the  part  of  the 
infective  agent  and  the  vertebrate  host,  although  in  some  in- 
stances several  species  of  mammals  may  apparently  serve 
equally  well. 

The  influence  of  temperature  and  rainfall  is  noticed  in  the 

1 80 


INSECTS    AS   VECTORS    OF    INFECTIVE    AGENTS  151 

distribution  and  prevalence  of  these  diseases,  due  to  the  effect 
which  these  climatic  factors  exercise  upon  the  breeding  oppor- 
tunities of  the  insects  and  hence  influence  their  abundance. 
Temperature  also  profoundly  influences  the  development  of  the 
protozoan  parasites  within  their  insect  hosts,  for  example  the 
distribution  of  malaria  is  limited  by  the  annual  isotherm  of  60 
degrees  F.  due  to  the  inability  of  the  malarial  parasites  to 
develope  in  the  mosquitoes  at  a  lower  temperature.  Thus 
low  temperature  may  even  inhibit  protozoan  development  or 
sterilize  the  insect  altogether.  On  the  other  hand,  with  favor- 
able conditions  of  temperature  it  would  appear  that  infection 
of  the  insect  is  usually  permanent. 

With  infective  agents  whose  transmission  is  biological,  a 
definite  lapse  of  time  must  occur  before  an  insect  which  has 
become  infected  can  transmit  the  infective  agents  to  the  host 
upon  which  it  feeds.  This  period  of  noninfectivity  is  known 
as  the  extrinsic  period  of  incubation  and  represents  the  time 
necessary  for  the  infective  agent  to  complete  its  sexual  cycle 
in    the    insect    and    reach    the    appropriate    point    of     exit. 

The  routes  by  which  the  mature  infecting  forms  of  the  in- 
fective agents  leave  their  arthropodal  hosts  varies  with  different 
species.  In  the  case  of  trypanosomes  present  in  Tse-tse  flies, 
departure  is  by  the  food  canal  of  the  probosis;  in  the  cases 
of  the  malarial  parasites  in  the  anophelines  the  departure  is  by 
the  salivary  ducts  in  the  probosis;  with  the  spirochetes  of 
relapsing  fever  in  either  lice  or  bedbugs  the  departure  may  be 
either  with  the  feces  through  the  anus,  or  by  liberation  from 
the  body  cavity  when  the  insect  is  crushed.  In  some  few  species 
hereditary  infection  of  the  insect  host  is  known,  thus  for  example 
the  piroplasms  of  Texas  Fever  pass  to  the  ovaries  and  young 
ticks  are  congenitally  infected.  The  same  also  occurs  in  African 
Relapsing  Fever. 

As  already  noted  the  infectivity  of  the  definitive  arthropodal 
host  is  influenced  by  :  (1)  external  temperature,  which  controls 
the  development  of  the  parasite  within  the  insect;  (2)  The 
digestive  processes  of  the  insect,  which  may  unfavorably  influence 
the  parasites;  and  (3)  the  presence  and  number  of  mature 
sexual  forms  of  1  he  parasites  in  the  blood  of  the  vertebrate  upon 
which  the  insect  has  fed.  Each  feeding  only  removes  a  very 
small  quantity  of  blood  and  unless  the  parasites  are  sufficiently 
numerous  in  the  blood  abstracted  and  both  sexual  forms  are 
present,  infection  of  the  insect  will  not  occur.  All  the  chances 
are  against  the  parasite.     Thus  we  can  understand  that  fre- 


152  PRACTICAL   PREVENTIVE    MEDICINE 

quently  only  one  or  two  per  cent,  of  anopheline  mosquitoes 
will  show  malarial  parasites,  yet  under  more  favorable  cir- 
cumstances where  heavy  gamete  carriers  are  abundant,  as 
many  as  20  to  25  per  cent,  of  mosquitoes  will  be  infected. 

The  ability  of  any  insect  transmitted  infection  to  gain  a  foot- 
hold and  maintain  itself  requires  at  least  two  conditions:  (1) 
That  the  definitive  insect  host  exist  in  a  certain  degree  of 
abundance,  and  (2)  That  intermediate  mammalian  hosts 
harboring  the  transmitting  stage  of  the-  parasite  be  accessable 
to  the  insects.  Thus  the  eradication  of  malaria  can  be  accom- 
plished without  absolutely  exterminating  all  anophelines  in  an 
area,  by  reducing  their  numbers  to  such  a  point  that  very  few 
if  any  anophelines  will  have  an  opportunity  to  bite  a  gamete 
carrier. 

2.  Mechanical  Insect  Transmission. — Transfer  of  infective 
agents  by  this  means  may  either  be  through  the  assistance  of 
biting  or  sucking  insects.  The  diseases  in  which  the  mech- 
anism is  more  or  less  clearly  understood  are  all  due  to  bacterial 
infective  agents.  The  relationship  of  the  insect  and  parasite 
is  not  specific,  that  is  the  parasite  can  be  transferred  from  man 
to  man  by  other  agencies  and  frequently  those  other  agencies 
are  of  greater  importance  in  the  propagation  of  the  different 
diseases  than  the  insects.  The  presence  of  infective  agents  in 
or  on  the  insect  is  more  contaminative  in  character,  the  insect 
relationship  does  not  play  any  essential  part  in  the  life  cycle 
of  the  parasite  and  commonly  we  find  that  the  insect  can  imme- 
diately transfer  infection  after  having  had  an  infective  meal. 
In  other  words  an  extrinsic  incubation  period  is  not  observed. 
Temperature  and  humidity  exercise  a  similar  influence  upon 
the  development  of  the  insect  vectors  of  this  group,  and  their 
influence  is  thus  exerted  and  manifested  in  the  seasonal  and 
climatic  distribution  of  these  diseases,  or  else  influence  the 
bacterium  within  or  upon  the  nsect.  The  diseases  whose 
infective  agents  may  be  transmitted  by  this  means  are  plague, 
cholera,  typhoid,  and  both  bacillary  and  amoebic  dysentery. 
Fleas  are  concerned  in  the  transmission  of  plague,  and  flies, 
principally  the  house  fly,  in  the  transmission  of  the  others.  In 
the  case  of  the  former,  the  plague  bacillus  leaves  the  flea's 
body  both  by  the  probocis  and  the  feces;  in  the  case  of  the  latter 
group,  the  flies'  probocis,  its  excreta,  regurgitated  material  and 
the  exterior  of  its  body  surface  may  afford  means  of  convey- 
ance. In  the  former  instance  the  infective  agents  are  directly 
reintroduced  by  the  insect  into  a  new  host,  in  the  latter  trans- 


INSECTS    AS   VECTORS    OF    INFECTIVE    AGENTS 


l83 


mission  is  effected  through  the  contamination  of  food  by  the 
insect. 

3.  The  Activity  of  the  House  Fly. — The  house  fly  (Musca 
domestica)  (Fig.  67)  is  an  ubiquitous  insect  with  a  world  wide 
distribution,  living  in  close  association  with  man.  Its  ova  are 
preferably  deposited  in  manure  piles,  from  these  hatch  the 
familiar  maggots  (Fig.  68),  which  burrow  through  the  pile 
and  feed  on  the  decaying  organic  matter.  In  about  a  week  in 
the  summer  these  leave  the  manure  and  burrow  in  the  soil 


Pig.  67. — The  house  fly.      {Public  Health  Reports,  Supplement  29.) 

where  they  pupate.  In  a  few  days  the  adult  fly  emerges.  The 
entire  life  cycle  may  be  completed  under  favorable  circum- 
stances in  from  10  to  14  days.  The  dangers  arising  from  this 
insect  are  due  to  its  promiscuous  feeding  habits  and  its  intimate 
association  with  man.  It  will  walk  over  and  feed  upon  the 
fecal  deposits  in  a  privy,  the  refuse  in  a  garbage  can,  the  pas- 
tries in  a  bake  shop  and  the  food  in  the  kitchen  and  pantry  with 
equal  impartiality  and  in  turn,  conveying  infective  agents 
secured  from  the  excreta  to  food  during  its  journey.  There  is 
absolutely  no  question  but  that  in  unsewered  cities  and  towns 


1 84 


PRACTICAL   PREVENTIVE    MEDICINE 


or  in  rural  areas  where  fly  tight  privies  are  not  used,  flies  are  a 
great  menace  and  an  actual  source  of  danger.  They  are  un- 
doubtedly a  considerable  factor  in  the  autumnal  increase  in 
typhoid.  A  very  marked  reduction  in  the  incidence  of  typhoid 
fever  was  secured  in  Jacksonville,  Florida  following  systematic 
efforts  at  fly  elimination  through  prevention  of  breeding,  the 
extension  of  the  sewer  system  and  the  substitution  of  fly  proof 
provies  for  open  closets.  Prior  to  1910  there  were  about  8,500 
privies  in  Jacksonville,  which  accommodated  about  40  per 
cent,  of  the  population.  They  were  distributed  uniformly 
over  the  entire  town.     None  were  fly  proof  in  the  slightest. 


Fig.  68.- 


-Larvse,    or  maggots,  of  the  house  fly.     About  natural  size    (Newstead). 
{Farmer's  Bull.  851.) 


The  typhoid  cases  annually  reached  a  maximum  in  the  fly 
season,  while  water  and  milk  could  be  eliminated  as  a  cause. 
In  1910  there  were  329  reported  cases  with  62  deaths.  Late 
in  1 9 10  an  ordinance  was  passed  requiring  the  fly  proofing  of 
all  privies,  a  requirement  that  was  completely  met  before  the 
season  of  191 1.  During  191 1  there  were  158  reported  cases 
and  40  deaths  and  in  191 2  87  cases  with  16  deaths.  Of  the 
191 1  cases  88  received  infection  outside  of  Jacksonville,  i.e., 
were  imported  and  of  the  191 2  cases  48  were  imported.  Later 
years  continued  to  show  the  same  results.  This  recalls  the 
experience  with  fly  borne  typhoid  in  the  southern  army  camps 


INSECTS    AS  VECTORS    OF   INFECTIVE    AGENTS  1 85 

during  the  Spanish  war,  in  which,  however,  the  role  of  the  flies 
was  not  recognized  until  serious  losses  occurred. 

Dysentery  bacilli  may  survive  in  flies  for  as  long  as  five  days, 
and  typhoid  bacilli  may  similarily  survive  nearly  seven  days. 
This  relates  to  the  organisms  in  the  flies  intestinal  tract,  from 
which  they  are  discharged  in  the  excreta  (fly  specks)  or  by 
regurgitation,  though  on  the  external  surface  of  the  body  their 
survival  is  brief. 

Difficulties  with  flies  can  best  be  overcome  by  the  elimination 
of  their  breeding  place,  namely  manure  piles.  These  if  open 
and  exposed  should  not  be  permitted  to  represent  over  a  weeks 
accumulation.  Stables  should  have  tight  floors  and  be  well 
cleaned.  The  removal  of  manure  at  weekly  intervals  will  re- 
move the  partially  developed  maggots  therein  and  afford  local 
relief,  but  however,  merely  transfer  the  difficulty  to  some  other 
situation.  Another,  but  more  expensive  method,  involves  the 
keeping  of  flies  from  manure  by  requiring  its  storage  in  fly 
tight  bins  or  boxes.  Another  solution  to  this  problem  is  afforded 
by  the  treatment  of  manure  piles  with  substances  which  destroy 
the  larvse.  Substances  must  be  used  which  are  not  too  expen- 
sive. Borax  may  be  used  at  the  rate  of  0.62  pounds  of  borax  per 
8  bushels  of  manure,  but  the  treated  manure  may  have  an 
injurious  effect  on  vegetation.  Powdered  hellebore,  using  one 
half  pound  to  10  gallons  of  water  and  applying  this  amount  to 
each  8  bushels  of  manure  is  perhaps  the  most  effective  and  prac- 
tical substances  to  use  for  this  purpose.  Trapping  and  other- 
wise catching  the  adult  flies,  particularly  if  practised  at  the 
beginning  of  the  breeding  season,  is  of  distinct  merit.  Sticky 
fly  paper  and  the  swatter  should  be  used  in  every  home  and 
eating  house.  Dwellings  and  eating  houses  should  be  screened, 
and  food  displayed  at  retail,  particularly  that  eaten  without 
further  heating,  should  also  be  screened. 

Traps  of  different  kinds  are  in  vogue,  some  of  which  are  de- 
signed to  be  placed  near  doors,  where  flies  seek  ingress,  others 
over  garbage  cans  or  manure  boxes,  are  all  of  value.  Unless 
attention  is  paid  to  the  breeding  places  however,  traps  are  of 
slight  service.  Garbage  accumulations  should  receive  atten- 
tion similar  to  manure. 

The  activity  of  flies  as  conveyers  of  infective  agents  from 
excreta  gives  opportunity  to  reiterate  the  importance  of  col- 
lecting human  excreta  in  privies  that  are  of  fly  tight  construction. 

4.  Insecticides. — Various  methods  are  available  for  the  de- 
struction of  insects  within  dwellings,  buildings,  vessels,  and  other 
enclosed  spaces.     Their  destruction  by  gaseous  poisons  is  the 


1 86  PRACTICAL    PREVENTIVE    MEDICINE 

most  satisfactory  method,  and  is  generally  applied  for  the  pur- 
pose of  destroying  either  the  types  which  have  a  closer  parasi- 
tism, such  as  fleas,  or  bed  bugs,  or  noxious  types  such  as  clothes 
moths,  cockroaches,  or  vectors  which  may  be  present  on  the 
premises  from  which  a  case  of  plague,  yellow  fever,  etc.,  has 
been  removed  and  hence  are  potentially  infected. 

For  this  purpose  either  sulphur  dioxid  or  hydrocyanic  acid 
gas  are  commonly  employed.  The  employment  of  gaseous  in- 
secticides demands  that  the  quarters  to  be  freed  of  insects  be 
given  the  same  preparation  as  that  required  for  disinfection. 
When  employed  as  an  insecticide,  it  is  not  necessary  that  water 
vapor  be  employed  with  the  burning  sulphur,  as  anhydrous  SO2 
is  effective.  For  this  purpose  two  pounds  of  sulphur  are  re- 
quired for  each  1000  cubic  feet  of  space.  Crushed  sulphur 
sticks  or  flowers  of  sulphur  should  be  employed.  The  required 
amount  of  sulphur  should  be  placed  in  a  conical  pile  in  a  very 
shallow  cast  iron  pot,  which  is  supported  on  bricks  in  a  tub  of 
water.  A  small  depression  is  made  in  the  summit  of  the  pile 
in  which  is  placed  a  ball  of  waste  or  cotton  saturated  with 
alcohol.  When  all  other  preparations  are  completed  the  alco- 
holic cotton  is  ignited  and  the  operator  immediately  makes  his 
escape.  The  quarters  should  remain  closed  for  from  2  to  12 
hours.  The  objectionable  features  of  sulphur  dioxid  have  been 
noted  in  the  consideration  of  disinfectants. 

A  more  satisfactory  insecticide  is  hydrocyanic  acid  gas.  It 
however  is  exceedingly  poisonous  to  all  mammals  and  man  and 
should  only  be  employed  by  one  who  is  thoroughly  competent 
and  who  fully  understands  its  dangers.  The  gas  is  liberated 
from  either  sodium  or  potassium  cyanid  by  means  of  sulphuric 
acid.  Per  1000  cubic  feet  of  the  followirg  proportion  of  these 
are  required: 

KCN 10      oz. 

H2SO4 15       oz. 

H20 22  .  5  OZ. 

Place  the  required  amounts  of  acid  and  water  in  a  glazed 
earthen  ware  jar,  observing  the  usual  precautions  in  the  mixing. 
Complete  all  other  preparations  and  be  ready  to  make  a  hurried 
exit.  Have  the  cyanid  wrapped  in  a  paper  and  drop  it  in  the 
jar  and  instantly  leave  the  room.  Keep  the  quarters  closed  at 
least  one  hour.  If  several  rooms  are  to  be  treated  some  ar- 
rangement with  slings  should  be  devised  for  lowering  the 
cyanid  into  the  acid  from  the  outside. 

Both  cyanid  and  SO2  are  also  employed  for  the  destruction 


INSECTS    AS   VECTORS    OF   INFECTIVE   AGENTS  1 87 

of  rodents.  In  maritime  quarantine  the  exhaust  gas  from  gaso- 
line engines  or  the  funnel  gas  from  burning  coal  are  also  em- 
ployed, due  to  the  large  content  of  carbon  monoxide  present. 
For  small  rooms  or  infrequent  treatment  it  is  not  practical. 

Another  substance  of  great  value  for  this  purpose  is  carbon 
bisulphid,  but  whose  wide  employment  is  limited  owing  to  its 
inflammable  and  explosive  qualities.  Carbon  bisulphid  volati- 
lizes rapidly  and  is  fully  as  explosive  as  ether.  The  gas  is 
heavier  than  air.  It  is  best  adapted  to  the  treatment  of  clothes 
rather  than  rooms  and  is  preferably  employed  in  small  air  tight 
closets  or  chests.  It  should  be  allowed  to  volatilize  in  the  pro- 
portion of  one  pound  per  ioo  cubic  feet.  The  container  from 
which  it  evaporates  should  be  placed  at  the  top  of  the  enclosed 
space.     It  should  be  allowed  to  act  for  10  to  12  hours. 

Insect  powders  have  some  value,  particularly  those  composed 
wholly  or  in  part  of  dried  pyrethrum  flowers.  These  are 
burnt,  or  diffused  through  the  air  as  a  powder.  The  vapor  or 
dust  stupefies  the  insects  so  they  fall  to  the  floor  and  may  be 
removed  by  sweeping.     Pyrethrum  is  not  injurious  to  man. 

The  body  louse,  because  of  its  intimate  relationship  to  man, 
cannot  be  altogether  controlled  by  fumigation  unless  the 
clothing  of  all  infected  individuals  is  fumigated  at  the  same 
time.  For  the  delousing  of  clothing  and  bedding,  physical 
agents  give  better  results  than  fumigants,  although  in  emer- 
gency work  circumstances  will  largely  control  ones'  efforts. 
Streaming  steam  will  kill  both  adult  lice  and  nits  in  20  minutes 
and  dry  heat  for  20  to  30  minutes  at  60  degrees  C.  will  also 
destroy  adults  or  nits.  Simultaneous  attention  must  be  paid 
to  lice  on  the  person,  particularly  in  the  hair.  The  old  standby 
of  kerosene  and  vinegar  is  probably  best  for  this  purpose. 

REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene.     3rd  Ed.,  Chap.  IV,  pp.  201. 

Doane:  Insects  and  Disease. 

Carbon  bi-sulphide  as  an  Insecticide.     Farmer's  Bull.  799,  U.  S.  Department 

of  Agriculture. 
Fleas  and  their  Control.     Farmer's  Bull.  897,  U.  S.  Dept.  Agr. 
Fly  traps  and  their  operation.     Farmer's  Bull.  73r,  U.  S.  Dept.  Agr. 
The  house  fly.     Farmer's  Bull.  851,  U.  S.  Department  of  Agr. 
The  transmission  of  disease  by  flies.     Supplement  29.     Public  Health  Reports. 
Further  experiments  in  the  destruction  of  fly  larvae  in  horse  manure.     Bull. 

245,  U.  S.  Dept.  Agriculture. 
The  stable  fly.     Farmer's  Bull.  540,  U.  S.  Dept.  of  Agr. 
Experimental    studies    of    muscicides    and    other    fly    destroying    agencies. 

Bull.  108,  Hygienic  Lab.  U.S.P.H.S. 
Hydrocyanic     acid    gas    against    household    insects.     Farmer's    Bull.     699 

U.  S.  Dept.  of  Agriculture. 


CHAPTER  XXI 

DISEASES  TRANSMISSIBLE  BY  INSECTS 

MALARIA 

i.  Infective  Agents. — (a)  Plasmodium  vivax,  causing  simple 
tertian  fever. 

(b)  Plasmodium  malaria  causing  quartan  fever. 

(c)  Plasmodium  falciparum,  causing  malignant  tertian  or 
estivo-autumnal  fever. 

2.  Source  of  Infection. — Human  beings  whose  blood  contains 
tne  gametes  or  sexual  forms  of  the  parasites,  either  those  having 
acute  or  chronic  malaria,  or  merely  carriers. 

3.  Portal  of  Exit. — Blood  abstracted  by  anopheline  mosquitoes. 

4.  Route  of  Transmission. — -Through  the  agency  of  anophe- 
line mosquitoes  which  have  bitten  persons  whose  blood  contains 
gametes.  The  sexual  cycle  of  the  parasite  requires  about  12 
days  for  completion  in  the  mosquito,  at  the  end  of  which  period 
the  infecting  forms  (sporozoites)  have  made  their  appearance 
in  the  salivary  glands  (extrinsic  period  of  incubation).  In  the 
United  States  there  are  three  species  of  anopheline  mosquitoes 
which  can  serve  as  vectors  namely  Anopheles  quadrimaculatus 
(maculipennis,  syn.)  (Fig.  69,  73),  Anopheles  punctipennis 
and  Anopheles  crucians.  Their  ova,  (Fig.  70)  are  most  com- 
monly deposited  in  open  collections  of  water  distant  from 
dwellings,  although  they  may  be  found  in  rain  barrels,  cisterns, 
etc.,  near  homes.  The  adults  are  nocturnal  in  their  habits. 
Only  the  females  are  blood  suckers  and  hence  only  the  females 
transmit  malarial  parasites.  External  temperatures  below 
15  to  16  degrees  C.  will  inhibit  the  development  of  the  parasite 
in  the  mosquito.  Of  the  three  species  the  quartan  can  develope 
at  the  lowest  temperature,  while  the  aestivo-autumnal  requires 
the  highest.  Adult  mosquitoes  that  successfully  hibernate 
are  rendered  sterile.  Infection  is  maintained  by  human  gamete 
carriers.  So  far  as  is  certainly  known  mosquitoes  are  not 
hereditarily  infected. 

5.  Portal  oj  Entrance. — Sporozoites  are  liberated  in  the  sub- 
cutaneous tissues  or  capillaries  by  the  discharge  of  the  salivary 
secretions  of  infected  mosquitoes  when  biting. 


DISEASES    TRANSMISSIBLE  BY   INSECTS 


189 


6.  Incubation  Period  {Intrinsic). — The  duration  of  this  period 
is  influenced  by  the  external  temperature,  being  shorter  during 


Fig.  69. — Anopheles  maculipennis.      {Ludlow:  Bull.  4.     Surgeon  General's  Office. 

War  Dep't.) 


Pig.   70. — Egg  of  anopheles,  dorsal  view.      (After  Nuttall  and  Shipley.)      (Doane: 
Insects  and  Disease,  Henry  Holt  and  Co.) 

high  temperatures.     It  is  usually  about  two  weeks  with  Plas- 
modium vivax.     The  length  of  time  following  the  onset  before 


190 


PRACTICAL   PREVENTIVE    MEDICINE 


gametes  appear  varies  with  the  different  species.  Thus,  in 
Tertian,  from  8  to  20  days;  Quartan,  11  days  (for  one  observa- 
tion);   Malignant  tertian,  from  10  to  35  days. 


' 


Fig.    71. — Anopheles  larvae,  the  one  to  the  right  feeding,  the  other  just  coming  to 
the  surface.      (Doane:  Insects  and  Disease,  Henry  Holt  and  Co.) 


Fig.   72. — Anopheles  pupas  resting  at   surface   of   water. 
Disease.     Henry  Holt  and  Co.) 


(Doane:  Insects  and 


Fig.  73.— Malarial  mosquito  (A.  maculipennis)  on  the  wall,  showing  the 
resting  posture  characteristic  of  Anophelines.  (Doane:  Insects  and  Diseases. 
Henry  Holt  and  Co.) 


DISEASES    TRANSMISSIBLE  BY   INSECTS  19I 

In  temperate  climates  infection  is  maintained  not  by  the 
survival  of  the  infected  mosquitoes  through  the  winter,  but  by 
the  reinfection  of  the  mosquitoes  from  human  gamete  carriers 
in  the  spring. 

7.  Period  oj  Communic ability. — As  long  as  gametes  are 
present  in  the  circulation.     This  may  be  indefinitely. 

8.  Methods  of  Control.  The  Injected  Individual  {Active 
Malaria). — [a)  Diagnosis:  Clinical  manifestations,  always  con- 
firmed by  detection  of  the  parasites  in  the  blood. 

(b)  Isolation:  Protection  of  the  patient  from  mosquitoes 
until  his  blood  is  free  from  parasites,  especially  gametes,  by 
the  use  of  screens  or  bars. 

(c)  Immunization:  None. 

(d)  Quarantine:  None. 

(e)  Concurrent  Disinfection:  None  as  such.  Destroy  by 
capture  or  swatting  all  mosquitoes  in  the  sick  room. 

(/)  Terminal  Disinfection:  Same  as  before. 

General  Measures. — (a)  Search  for  gamete  carriers  by  the  exam- 
ination of  blood  smears.  Intensively  treat  such  persons  with 
quinine  until  sterilized.  For  adults  Bass  recommends  10  grains  of 
quinine  sulphate  every  night  before  retiring,  continued  for  8  weeks 
This  treatment  will  destroy  the  parasites  in  90  per  cent,  of  the 
carriers.  The  remaining  10  per  cent,  should  receive  3,  ten- 
grain  doses  a  day  for  three  or  four  days  and  later  10  grains  a 
day  for  eight  weeks.  Infants  and  children  should  be  dosed  as 
follows: 

Under  1  year 0.5  grain       . 

1  year 1 .0  grain 

2  years ' 2.0  grain 

3  to  4  years 3.0  grain 

5,  6  and  7  years 4.0  grain 

8,  9  and  10  years 6.0  grain 

1 1-14  years 8.0  grain 

15  years 10. o  grain 

(b)  Prophylactic  administration  of  quinine:  The  daily  admin- 
istration of  3  grains  of  quinine  will  prevent  infection  from  de- 
veloping. Where  employed  on  a  large  scale  provision  must 
either  be  made  for  its  distribution  gratis  or  at  a  very  low  charge. 

(c)  Destruction  of  mosquito  breeding  places,  by: 

1.  Drainage  (Figs.  76,  77). 

2.  Training  of  water  courses,  or  by 

3.  Filling. 


192 


PRACTICAL    PREVENTIVE    MEDICINE 


Attention  should  be  paid  to  all  depressions  both  natural  and 
artificial,  and  of  either  stagnant  or  running  water  within  one 
half  mile  radius  of  the  area  where  control  operations  are  being 
prosecuted. 

The  planting  of  eucalyptus  trees  in  swampy  wet  areas  that 
for  one  reason  or  another  cannot  be  drained,  has  been  recom- 
mended, but  their  value  for  this  purpose  is  undetermined. 
They  apparently  accelerate  the  evaporation  of  the  swamp 
water. 

(d)  Destruction  of  Mosquito  Larvae.  Two  methods  may 
be  used. 


Pig.  74. — Oilers  at  work  in  marsh.      (Gorgas,  "  Sanitation  in  Panama,"  Appleton's.) 


i.  The  application  of  a  thin  iridescent  film  of  oil  to  the  sur- 
face of  water  areas  it  is  not  feasible  to  drain,  at  least  after  every 
rain.  The  oil  is  either  sprayed  from  knapsack  sprays,  or  fed 
by  drip  cans.  The  latter  are  only  adapted  to  streams  or  ditches 
conveying  running  water.     Crude  oil  is  best  (Figs.  74,  75). 

3.  Stocking  swamps  and  pools  with  species  of  fish  that  are 
predatory  upon  mosquito  larvae.  The  Public  Health  Service 
is  introducing  the  employment  of  the  top  minnow,  Gambusia 
affinis,  for  this  purpose. 

2.  The  application  of  solutions  having  a  lethal  action  on  the 
larvae,  such  as  the  "Larvacide"  of  Darling.     This  is  prepared 


DISEASES    TRANSMISSIBLE   BY   INSECTS 


[93 


from  crude  carbolic  acid  of  a  sp.  gr.  not  greater  than  0.97  and 
containing  not  less  than  30  per  cent,  tar  acids.     One  hundred 


pIG_   7,^ — Burning  out  ditch  with  oil  spray.      (Gorgas,  "Sanitation  in  Panama, 

Appleton's.) 


Fig.   76. — Prolific    source    of    anopheles,   horse-lot   drain,  Crossett.      (Derivaux, 
Taylor  and  Hess,  P.  H.  Bull.  88,  U.  S.  P.  H.  S.) 

and  fifty  gallons  of  the  phenol  are  heated  in  a  tank  and  to  this 
200  pounds  of  finely  crushed  and  sifted  rosin  are  added  and  also 
30  pounds  of  caustic  soda  dissolved  in  6  gallons  of  water.     This 

13 


194 


PRACTICAL   PREVENTIVE    MEDICINE 


is  well  mixed.  For  use  a  1 15  dilution  in  water  is  made.  This  is 
sprayed  on  water  accumulations  until  the  water  has  a  thin 
milky  opalescence  (about  1:5000). 

In  applying  either  oil  or  larvacide  especial  attention  must  be 
given  to  the  margins  and  weedy  places  in  the  streams  and  pools. 
Depending  upon  the  degree  of  agitation  and  the  amount  of 
fresh  water  introduced  by  rain,  etc.,  repeated  application  of 
these  will  have  to  be  made  at  irregular  intervals. 

(e)  Destruction  of  Adult  Mosquitoes:  1.  Adult  mosquitoes 
may  be  naturally  destroyed  by  the  encouragement  of  various 
natural  predaceous  enemies,  such  as  bats,  dragon  flies,  etc. 
These  alone,  however,  will  not  suffice. 


Pig.  77. 


-Same  as  Pig.  76,  after  treatment.      (Derivaux,  Taylor  and  Hess.     P.  H. 
Bull.  88,  U.  S.  P.  H.  S.) 


2.  Swatting  or  trapping  of  adult  mosquitoes  in  dwellings: 
They  prefer  to  hide  in  dark  corners  during  the  day,  where 
patient  search  will  soon  result  in  their  discovery.  One  may  also 
fumigate  by  burning  pyrethrum. 

(/")  Exclusion  of  adult  mosquitoes  from  dwellings. 

Screening  is  the  best  method  of  accomplishing  this  result. 
A  fine  mesh  screen  of  at  least  19  to  20  strands  per  inch  should 
be  employed.  All  external  openings  should  be  screened,  in- 
cluding windows,  doors,  fireplaces,  or  chimneys,  cracks,  etc. 
If  possible  verandas  or  galleries  should  be  screened,  rather  than 
to  limit  one's  efforts  to  the  windows  and  doors  leading  out 
upon  them.  Doors  may  be  protected  by  screened  vestibules 
if  necessary.  In  the  absence  of  screening  bars  should  be  pro- 
vided for  all  beds. 


DISEASES    TRANSMISSIBLE  BY   INSECTS  195 

Screening  and  the  control  of  mosquito  breeding  on  the  living 
premises  are  remedies  available  to  every  householder.  On  the 
other  hand,  the  elimination  of  areas  of  extensive  breeding  is 
an  effort  that  requires  concerted  community  action.  The 
methods  or  combinations  of  methods  required  to  meet  local 
conditions  will  vary,  and  require  the  exercise  of  considerable 
judgment.  The  question  of  initial  cost  and  maintenance 
costs  will  likely  be  factors  that  largely  influence  the  permanency 
of  the  efforts.  At  Havana,  Panama,  lsmailia  and  a  few  other 
places,  the  importance  of  mosquito  control  to  the  authorities  was 
such  that  expense  was  not  considered  in  securing  the  desired 
result.  On  the  other  hand,  the  control  of  malaria  in  the 
southern  United  States  is  a  problem  that  will  only  be  solved  by 
methods  that  are  within  the  slender  resources  of  the  average 
rural  community.  The  possibilities  in  this  direction  have  been 
brilliantly  demonstrated  by  the  work  of  Dr.  H.  A.  Taylor  in  a 
group  of  rural  towns  in  south  eastern  Arkansas.  In  the  four 
towns  in  which  antimosquito  measures  were  undertaken  in  19 18, 
there  was  an  average  reduction  in  the  incidence  of  malaria  of 
89  per  cent.  The  operations  included  the  cutting  of  new  drain- 
age ditches  where  necessary,  the  recleaning  and  regrading  of 
old  streams  and  the  oiling  of  all  accumulations  of  water  not 
possible  to  drain.  This  was  accomplished  at  an  average  per 
capita  cost  of  eighty  eight  cents.  The  work  requires  careful 
and  intelligent  supervision. 

YELLOW   FEVER 

i.  Injective  Agent. — Probably  the  spirochete  (Leptospira 
icteroides)  reported  by  Noguchi. 

2.  Source  oj  Injection. — Typical  and  atypical  cases  of  yellow 
fever,  possibly  only  during  the  first  three  days  of  their  illness. 

3.  Portal  oj  Exit. — Blood  abstracted  by  Stegomyia  jasciata 
(Aedes  calopus)  (Fig.  78). 

4.  Route  oj  Transmission. — So  far  as  known  only  by  the 
agency  of  one  species  of  mosquito,  Stegomyia  jasciata,  which 
has  fed  upon  the  blood  of  yellow  fever  patients.  The  unknown 
parasite  undergoes  an  extrinsic  incubation  period  in  the 
mosquito  of  at  least  12  days  before  the  mosquito  can  transmit 
the  virus. 

5.  Portal  oj  Entrance. — Through  the  puncture  wounds  in  the 
skin  made  by  mosquitoes,  to  the  subcutaneous  tissues. 

6.  Incubation  Period. — (Intrinsic)  from  three  to  six  days. 


196 


PEACTICAL   PREVENTIVE    MEDICINE 


7.  Period  oj  Communicability. — Probably  only  during  the 
first  three  days  of  the  illness. 

8.  Methods  of  Control.  The  Injected  Individual. — (a)  Di- 
agnosis: Clinical  observations  only. 

(b)  Isolation:  In  a  well  screened  room  or  ward  which  has 
been  freed  of  mosquitoes. 

(c)  Immunization:  None. 

(d)  Quarantine:  Of  contacts  for  six  days. 

(e)  Concurrent  Disinfection:  None. 

(/)  Terminal  Disinfection:  Fumigate  to  get  rid  of  mosquitoes. 

General  Measures. — (a)  Eradication  of  mosquitoes  by  meas- 
ures described  under  malaria.  Since  the  habits  of  Stegomyia 
differ  from  those  of  anophelines,  some  difference  in  the  water 
accumulations  attacked  must  be  noted.  The  Stegomyia  is  a 
species  that  lives  closely  in  association  with  man,  breeding  largely 


Pig.  78. — The  yellow-fever  mosquito:  Adult  female,  side  view.  Much  en- 
larged. The  silver  and  black  markings  give  the  insert  a  very  striking  appear- 
ance.     Note  the  silver  crescents  on  the  thorax.      (Howard:  Farmer's  Bull.  547.) 

in  artificial  accumulations  of  water  close  to  dwellings,  such 
as  cisterns,  barrels  and  cans  (Fig.  79).  It  is  diurnal  in  its 
first  feeding  and  later  nocturnal.  It  is  never  found  in  marshes 
or  swamps,  so  that  attention  need  not  be  given  to  these  unless 
a  simultaneous  attack  on  malaria  is  also  desired 

Epidemic  Measures. — (a)  Inspection  service  to  detect  un- 
reported cases. 

(b)  Fumigation  of  houses  in  which  cases  have  occurred, 
and  also  of  the  adjacent  houses. 

(c)  Removal    of    patients    to    screened    isolation  hospitals. 

DENGUE 

i.  Infective    Agent. — Unknown. 

2.  Source  oj  Injection. — So  far  as  is  known  only  typical  and 
atypical  human  cases. 


DISEASES    TRANSMISSIBLE   BY    INSECTS  I97 

3.  Portal  of  Exit. — In  the  blood  abstracted  from  patients. 

4.  Route  of  Transmission. — By  agency  of  mosquitoes  (Steg- 
omyia  fasciata)  which  have  fed  upon  dengue  patients.  The 
extrinsic  incubation  period  is  unknown. 

5.  Portal  of  Entrance. — Through  puncture  wounds  made  by 
mosquitoes  in  the  skin,  into  the  subcutaneous  tissues. 

6.  Incubation  Period. — From  four  to  five  days     (intrinsic). 

7.  Period  of  Communicability. — Probably  as  late  as  the 
eighth  day  of  illness. 

8.  Methods  of  Control.  The  Injected  Individual. — (a)  Diag- 
nosis :  Clinical  manifestations. 

(b)  Isolation:  In  a  screened  room. 

(c)  Immunization:  None. 

(d)  Quarantine:  None. 

(e)  Concurrent  Disinfection:  None. 

(/)  Terminal  Disinfection :  Fumigate  to  get  rid  of  mosquitoes. 
General  Measures. — Same  as  for  Yellow  Fever. 

TYPHUS  FEVER 

i.  Infective  Agent. — Unknown. 

2.  Source  of  Infection. — Typical  and  atypical  human  cases. 

3.  Portal  of  Exit. — In  blood  abstracted  from  patients. 

4.  Route  of  Transmission. — By  the  agency  of  the  human 
body  or  clothes  louse,  Pediculus  vestimenti  (Fig.  80).  The 
virus  appears  to  have  an  extrinsic  incubation  period  in  the  louse 
of  at  least  four  days. 

5.  Portal  oj  Entrance. — Through  puncture  wounds  in  the 
skin  made  by  lice,  into  the  subcutaneous  tissues. 

6.  Incubation  Period  {Intrinsic). — From  five  to  twenty  days, 
usually  twelve  days. 

7.  Period  oj  Communicability. — Probably  until  one  or  two 
days  following  the  return  of  patient's  temperature  to  normal.' 

8.  Methods  of  Control.  The  Infected  Individual.- — (a)  Diag- 
nosis: By  clinical  manifestations.  The  Felix- Weil  agglutina- 
tion reaction  is  reported  as  of  value. 

(b)  Isolation:  Destroy  all  vermin  on  the  body  of  the  patient, 
transfer  to  vermin  free  clothing  and  place  in  a  vermin  free  room. 
All  attendants  should  wear  vermin  proof  clothing. 

(c)  Immunization:  None. 

(d)  Quarantine:  Of  those  exposed,  or  of  susceptibles  for 
twelve  days  after  last  exposure. 

(e)  Concurrent    Disinfection:  None. 


iq8 


PRACTICAL   PREVENTIVE   MEDICINE 


(/)  Terminal  Disinfection:  Destroy  all  lice,   together  with 
their  eggs,  on  the  patient's  body  if  not  already  done.     Destroy 


Fig.  79. — Screened  water  barrel,  Havana.     (Gorgas,  "Sanitation  in  Panama," 

Appleton's.) 


Fig.  80. — Pediculus    vestimenti.     L.:    female    (X   about    25).     {Castellani   and 
Chalmers,  "Manual  of  Tropical  Medicine,"  Wm.  Wood  and  Co.). 

all  vermin  and  eggs  on  the  clothing  returned  to  the  patient. 
Free  the  isolation  quarters  of  all  vermin. 

General  Measures. — Delousing  of  persons,  clothing  and  prem- 


DISEASES    TRANSMISSIBLE   BY   INSECTS 


199 


ises  during  epidemics,  or  when  individuals  have  come  into  or 
have  been  brought  into  an  uninfected  place  from  an  infected 
community.     (Figs.  81,  82.) 


Fig.  81. — Delousing  equipment  of  the  Santa  Fe  Railroad.     (Am.  Jour.   Pub. 

Health,  7-8.) 

EUROPEAN    RELAPSING    FEVER 

i.  Infective  Agent. — Spironema  recurrentis  {Syn.  Spirillum 
obermeirii) . 

2.  Source  of  Infection. — Typical  and  atypical  human  cases. 

3.  Portal  of  Exit. — In  the  blood  abstracted  from  patients. 

4.  Route  of  Transmission. — By  the  agency  of  the  common  bed 
bug,  Cimex  lectularius.  (Fig.  83).  The  duration  of  the  period 
of  extrinsic  incubation  is  unknown.  Possibly  also  by  body 
lice. 

5.  Portal  of  Entrance. — Through  puncture  wounds  made  in 
the  skin  by  bugs  and  lice,  and  also  through  abrasions  made  by 
scratching,  into  which  have  been  rubbed  the  body  juices  of 
crushed  bugs. 

6.  Incubation  Period.  {Intrinsic). — From  two  to  twelve 
days. 


200 


PRACTICAL   PREVENTIVE   MEDICINE 


7.  Period  of  Communicability.— Unknown.  Regard  a  patient 
as  possibly  infective  until  recovery  is  complete. 

8.  Methods  of  Control.  The  Injected  Individual. ^-{d)  Diag- 
nosis: Clinical  manifestations  confirmed  by  the  observation 
of  the  spirillum  in  blood  smears  taken  during  relapses. 


a -2 
•°3  3.§  §1 

(&)  Isolation:  Same  as  for  typhus. 

(c)  Immunization:  None. 

(d)  Quarantine:  Of  exposed  susceptibles  for  twelve  days  after 
the  last  exposure. 


DISEASES    TRANSMISSIBLE   BY   INSECTS  201 

(e)   Concurrent  Disinfection:  None. 
(/)  Terminal  Disinfection:  Same  as  for  typhus. 
General  Measures. — Same  as  for  typhus,  extending  the  ac- 
tivities to  include  the  bed  bugs. 


Fig.  83. — Cimex  lectularius.  a.  Adult  female,  gorged  with  blood;  b,  same 
from  below;  c,  rudimentary  wing-pad;  d,  mouth-parts — all  enlarged.  (Marlait, 
Bull.  4,  Div.  Rnt.). 

REFERENCES 

Ross:  The  Prevention  of  Malaria. 

Quinine  Prophylaxis  for  Malaria.     Reprint  454,  Public  Health  Reports. 

Oiling  as  an  Anti-Mosquito  Measure.     Reprint  260,  Public  Health  Reports. 

Drainage  as  an  Anti-Malarial  Measure.     Reprint  258,  Public  Health  Reports. 

Malaria  Control:  Public  Health  Bull.  88,  U.S.P.H.S. 

Yellow  Fever:  its  epidemiology,   prevention  and   control.     Supplement    19, 

Public  Health  Reports,  U.S.P.H.S. 
The  Administration  of  a  Yellow  Fever  Campaign.     Supplement  15,  Public 

Health  Reports,  U.S.P.H.S. 
Boyd:  The   Delousing   Measures  of  the   Santa   Fe   Railway   System.     Am. 

Jour.  Public  Health,  Vol.  7,  667. 
Field    Identification    of    Malaria    Carrying    Mosquitoes.     Supplement    32, 

Public  Health  Reports. 
Suggestions  on  How  to  Screen  the  Home  to  Keep  Out  Effectively  the  Mos- 
quitoes Which  Spread  the  Disease.     Reprint  170,  Public  Health  Reports. 
Anopheline  Surveys:  Methods  of  Conduct  and  Relation  to  Anti-Malarial 

Work.     Reprint  272,  Public  Health  Reports. 
Methods  of  Destroying  Lice.     Reprint  293,  Public  Health  Reports. 
Destroying  Lice   on   Typhus   Fever   Suspects.     Reprint  370,  Public  Health 

Reports. 
The  Yellow  Fever  Mosquito.     Farmer's  Bull.  347,  U.  S.  Dept.  Agriculture. 
Malarial  index  work.     Reprint  159,  Public  Health  Reports. 


202  PRACTICAL   PREVENTIVE   MEDICINE 

Typhus  Fever.     Reprint  271,  Public  Health  Reports. 

Malaria  in  the  United  States.     Reprint  277,  Public  Health  Reports. 

Carbon   Tetrachloride  as    a  Delousing  Agent.     Reprint  489,  Public  Health 

Reports. 
The    Transmission    of    Typhus     Fever,    etc.     Reprint    74,    Public    Health 

Reports. 
Studies  on  the  Virus  of  Typhus.     Reprint  82,  Public  Health  Reports. 
The  Felix-Well  reaction  as  a  laboratory  test  in  the  diagnosis  of  typhus  fever. 

Public  Health  Reports,  Vol.  34,  p.  2446. 


CHAPTER  XXII 

LOWER    ANIMALS    AS    SOURCES    OF    INFECTION 

FOR  MAN 

The  lower  animals,  both  wild  and  domesticated,  suffer  from 
a  number  of  infections  whose  agents  are  transmissible  to  man. 
The  more  important  are  the  following: 


Frequency 


Disease 


Animal  host 


A.  Transmission   regular 

i. 

Bubonic  Plague. 

Rats,   by   the   agency   of 

or  at  least  frequent. 

fleas. 

2. 

Rabies. 

Dogs  and  other  carnivora. 

3- 

Anthrax. 

Sheep,  cattle  and  horses. 

4- 

Trichiniasis. 

Swine. 

5- 

Malta  Fever. 

Goats. 

6. 

Rocky  Mt.  Fever. 

Ground  squirrels  by  ticks. 

7- 

Tape  Worms. 

Cattle,  swine  and  dogs. 

B.  Transmission  limited. 

8. 

Cow  pox. 

Cattle. 

9- 

Bovine  tuberculosis. 

Cattle. 

10. 

Glanders. 

Horse,  donkey  and  mule. 

11. 

Paratyphoid. 

Cattle  and  swine. 

12. 

Foot  and  mouth  dis- 
ease. 

Cattle  and  swine. 

13. 

Fungi   of   favus   and 
ring-worm. 

Mice  and  cattle. 

Because  of  their  rarity  in  man,  or  their  triviality  as  causes 
of  mortality,  we  shall  ignore  certain  of  these  infections  and 
confine  our  attention  to  five.  These  infections  are  transmitted 
to  man  by  varying  routes,  the  only  common  feature  being 
the  fact  that  man  is  not  the  normal  host  of  the  infective  agent. 


PLAGUE  (BUBONIC  AND  PNEUMONIC) 

1.  Infective  Agent. — Bacterium  pestis. 

2.  Source  of  Infection. — Typical  and  atypical  plague  (acute 
and  chronic)  in  rats  and  other  rodents,  including  the  native 
ground   squirrels   in    California.     In   pneumonic   plague   man 

203 


204 


PRACTICAL    PREVENTIVE    MEDICINE 


serves  as  the  source  of  infection.     The  disease  normally,  how- 
ever, is  one  of  rodents. 

3.  Portal  of  Exit. — The  blood  of  infected  rats  abstracted  by 
fleas,  or  the  sputum  of  pneumonic  plague  patients. 

4.  Route  of  Transmission. — In  bubonic  and  septicemic  plague 
the  bacillus  is  conveyed  from  rat  to  man  or  from  rat  to  rat  or 
other  rodent,  by  the  agency  of  either  the  tropical  rat  flea 
[Loemopsylla  ckeopis)  or  the  temperate  zone  rat  flea  (Cerato- 
phyllas  fasciatus)  (Fig.  84).  Their  action  is  purely  mechanical. 
The  plague  bacilli  produce  an  intestinal  obstruction  in  the 
flea,  so  that  an  infected  flea  when  attempting  to  feed  regurgi- 


Fig.   84. — The    European    rat    flea    (Ceratophyllus   fasciatus):  adult    female. 
Greatly  enlarged.      (Bishopp:  Bull.  248.      U.  S.  Dept.  of  Agriculture.) 

tates  plague  bacilli  from  his  stomach  into  the  punctured  wound. 
Bed  bugs  {Cimex  lectularius)  may  also  transmit  the  bacilli. 

In  pneumonic  plague  the  bacilli  are  transferred  from  man  to 
man  by  direct  or  indirect  contact. 

5.  Portal  of  Entrance. — The  fleas  may  introduce  the  bacilli 
into  the  subcutaneous  tissues  of  any  part  of  the  body,  usually 
into  the  lower  extremities. 

In  pneumonic  infection  the  bacilli  are  introduced  into  the 
body  either  through  the  mouth,  nose  or  conjunctiva. 

6.  Incubation  Period. — Commonly  from  three  to  seven  days, 
though  sometimes  prolonged  to  eight  or  even  fourteen  days. 

7.  Period  of  Communicability. — (a)  Man:  Until  convales- 
cence is  well  established,  period  undetermined. 


LOWER   ANIMALS    AS    SOURCES    OF   INFECTION   FOR   MAN  205 

(b)  Rat:  In  chronic  or  latent  cases  the  infectivity  may  be 
prolonged,  but  the  period  is  uncertain. 

8.  Methods  of  Control.  The  Infected  Person.— (a)  Diagno- 
sis: Clinical  manifestations  confirmed  by  bacteriological  ex- 
amination of  blood,  glandular  exudate  or  sputum. 

(b)  Isolation:  i.  Bubonic  plague:  Hospitalize  if  possible, 
place  patient  in  a  vermin  free,  screened  room. 

2.  Pneumonic  plague:  Rigid  isolation  must  be  employed  and 
attendants  must  exercise  great  care  for  their  own  protection. 
Masks  should  be  worn. 

(c)  Immunization:  Yersin  produced  a  serum  by  the  in- 
jection of  horses  at  first  with  a  plague  vaccine  and  later  com- 
pleting the  immunization  by  the  use  of  living  cultures^  The 
therapeutic  value  of  the  serum  is  appreciable.  Active  immu- 
nization with  Haffkine's  vaccine  apparently  confers  protection. 
The  Indian  experience  appears  to  indicate  that  the  likelihood  of 
subsequent  infection  after  its  use  is  reduced  four  fifths,  while 
among  the  proportion  who  do  contract  infection,  the  chances 
of  recovery  are  much  increased.  It  should  be  administered  to 
those  persons  whose  activities  favor  their  exposure. 

(d)  Quarantine:  Of  contacts  for  seven  days. 

(e)  Concurrent  Disinfection:  Of  all  discharges  and  articles 
soiled  therewith. 

(/)  Terminal  Disinfection:  Thorough  cleaning  followed  by 
thorough  disinfection. 

General  Measures. — (a)  Extermination  of  rats  and  vermin 
within  the  infected  area,  paying  especial  attention  to  the  brown 
or  Norway  rat  by  employing : 

1.  Fumigation  with  HCN,  S02,  CO  or  CS2. 

2.  Trapping. 

3.  Poisoned  bait. 

(b)  Rat  exclusion. 

1.  By  rat  proofing  homes,  outhouses,  and  business  buildings 
(Figs.  86,  87,  88,  89).  m  m 

2.  By  removing  accumulations  of  refuse  in  which  rats  can 
harbor,  and  of  garbage  upon  which  they  can  feed. 

3.  By  exterminating  rats  on  ships. 

4.  By  preventing  rats  on  ships  from  coming  ashore,  or  those 
on  shore  from  entering  ships  (Fig.  90).  The  marine  migrations 
of  rats,  accomplished  by  the  aid  of  shipping,  have  in  the  last 
twenty  five  years  distributed  plague  over  the  entire  world. 

(c)  Flea  destruction  by  fumigation.  This  should  be  em- 
ployed in  infected  foci. 


2o6 


PRACTICAL    PREVENTIVE    MEDICINE 


Pig.  85. — Generalview  of  stable  and  junk  house  from  second  floor.  Two 
plague  rats  were  trapped  here.  On  demolition  86  rats  were  killed.  (Public 
Health  Reports.) 


Fig.  86. — Model   showing   construction   details   which   permit    rat   infestation. 
(Suppl.    27,    Public    Health    Reports,    U.    S.    P.    H.    S.) 


LOWER   ANIMALS    AS    SOURCES    OF   INFECTION   FOR   MAN  207 

(d)  Delimitation  of  an  infected  area:  General  rat  trapping 
operations  should  be  carried  out  all  over  an  infected  area.  All 
rats  caught  and  all  found  dead  should  be  examined  for  evi- 


Fig.  87. — Rat-proofing  lumber  by  elevation  on  concrete  pillars.     (U.  S.  P.  H.  S.) 

dence  of  plague  infection.     The  locality  where  each  infected 
rat  is  found  should  be  regarded  as  a  focus  of  infection.     Since 


Fig.  88. — Site  of  human  plague  in  Puerta  de  Tierra.     Rat  proofed  by  concrete 
walls  and  floor.      (P.  H.  Rep.,  June  6,  IQ13O 

permanent  measures  of  rat  exclusion  and  eradication  are  ex- 
pensive and  procede  slowly,  it  is  not  always  practicable,  in  the 
face  of  existing  plague,  to  enforce  these  generally  with  the  hope 


208 


PRACTICAL    PREVENTIVE    MEDICINE 


of  eradicating  the  disease.     A  more  practicable  method  is   to 
confine  the  earliest  operations,  at  any  rate,  to  the  infected  foci 


Pig.  89. — 


Site  where  a  plague  rat  was  found,  after  elevation.     Building  formerly 
tight  to  the  ground.      {P.  H.  Rep.,  June  6,  1913.) 


Pig.  90. — The  rat  guards  on  the  hawsers  prevent  rats  entering  or  leaving  the 
ship  by  this  route.     The  ship  should  also  be  breasted  from  the  wharf. 

until  the  disease  is  brought  under  control.     The  method  de- 
veloped by  Heiser  in  Manila  for  this  purpose  is  as  follows: 


LOWER   ANIMALS    AS    SOURCES    OE   INFECTION   FOR   MAN  209 

Five  radiating  equidistant  lines  are  drawn  from  each  point 
where  a  plague  rat  is  found.  Starting  at  the  center,  rat  catch- 
ing operations  are  carried  out  along  each.  The  most  distant 
points  along  each  line  at  which  plague  rats  are  found  are  con- 
nected by  lines.  Thus  the  circumference  of  the  infected  area  is 
outlined  (See  Fig.  90a).  As  a  rule  its  radius  is  seldom  more  than 
a  few  blocks  from  the  original  focus.  Rat  catching  is  then  be- 
gun along  the  periphery  and  proceeds  toward  the  center,  after 


Pig.  90a. 


-Isolated    plague-infested    center,    Manila,  P.  I. 
and  Public  Health,    U.  S.  P.  H.  S.) 


(From  Heiser;  Rat 


which  rat  proofing  operations  are  begun  at  the  periphery  and 
proceeds  centrally.  Thus  the  rodents  in  each  focus  are  ex- 
terminated and  the  place  made  uninhabitable  for  them.  This 
method  has  not  been  employed  in  combatting  plague  in  the 
United  States. 

(e)  In  California  considerable  effort  is  being  made  to  eradi- 
cate the  ground  squirrels  in  infected  rural  areas  by  use  of  poi- 
soned grain,  trapping,  and  asphyxiation  of  the  squirrels  in  their 
burrows  by  carbon  bisulphide. 


14 


2IO  PRACTICAL    PREVENTIVE    MEDICINE 

(/)  House  to  house  inspection  for  the  detection  of  unreported 
cases  may  be  necessary.  All  dying  during  the  epidemic  should 
be  autopsied. 

(g)   Cremation  or  burial  in  quick  lime  is  advisable. 

ROCKY  MOUNTAIN  SPOTTED  FEVER 

i.  Infective  Agent. — Unknown. 

2.  Source  of  Infection. — Ground  squirrels  and  other  rodents 
of  the  western  inter-mountain  region  of  the  United  States. 

3.  Portal  of  Exit. — Blood  of  infected  animals  abstracted  by 
ticks  of  the  genus  Dermacentor. 

4.  Route  oj  Transmission. — By  bites  of  ticks  (Dermacentor 
andersonii,  or venustus.  (See  Fig.  91),  which  have  fed  on  infected 
ground  squirrels.     Probably  a  biological  transmission. 

5.  Portal  oj  Entrance. — Into  the  subcutaneous  tissues  through 
the  bite  wound. 

6.  Incubation  Period. — Three  to  ten  days,  usually  seven 
days. 

6.  Incubation  Period. — Three  to  ten  days,  usually  seven  days. 

7.  Period  oj  Communicability. — Unknown. 

8.  Methods  of  Control.  The  Injected  Person. — (a)  Diag- 
nosis: By  clinical  manifestations  in  areas  where  the  disease  is 
known  to  be  endemic. 

(b)  Isolation:  None. 

(c)  Immunization:  None. 

(d)  Concurrent  Disinfection:  None,  but  destroy  any  ticks 
that  may  be  on  the  patient. 

(e)  Quarantine:  None. 

(J)  Terminal  Disinfection:  None. 

General  Measures. — (a)  The  wearing  of  tick  proof  clothing 
by  those  in  endemic  areas,  and  following  the  practice  of  search- 
ing the  body  each  day  for  ticks. 

(b)  Destroying  ticks  on  limited  zones  in  infected  areas  by 
clearing,  and  burning  vegetation  in  rotation. 

(c)  Grazing  sheep  on  infected  areas.  The  ticks  attach 
themselves  to  the  sheep,  become  enmeshed  in  the  wool  and 
perish. 

(d)  Dipping  of  the  other  domestic  animals  of  infected  areas 
in  arsenical  solutions. 

(e)  Destruction  of  ground  squirrels,  chipmunks  and  other 
rodents  in  infected  areas  by  poisoned  grain,  by  CS2  and  by 
trapping. 


LOWER   ANIMALS    AS    SOURCES    OF   INFECTION   FOR   MAN  211 


Fig.  91. — The  RockyMountain  spotted-fever  tick,  Dermacentor  venustus.^  1. 
"  Deposited-out "  female  with  eggs.  2.  Unengorged  larva.  3.  "  Deposited- 
out"  female,  frontal  view.  4.  Engorged  larva.  5.  Engorged  female,  dorsal 
view.  6.  Unengorged  female,  dorsal  view.  7.  Male,  dorsal  view.  8.  Male, 
ventral  view.  9.  Unengorged  female,  ventral  view.  (Hooker,  Bishopp  and 
Wood,  Bull.  106,  Bureau  of  Entomology,  U.  S.  Dept.  of  Agriculture.) 


212  PRACTICAL   PREVENTIVE    MEDICINE 

RABIES 

i.  Infective  Agent. — Unknown,  a  filterable  virus. 

2.  Source  o]  Infection. — Typical  and  atypical  cases  and  incu- 
batory carriers  in  dogs,  and  other  carnivorous  animals. 

3.  Portal  oj  Exit.- — In  the  saliva  of  infected  animals. 

4.  Route  oj  Transmission.- — Inoculation  with  the  saliva  of 
infected  animals,  through  wounds  or  abrasions  of  the  skin  and 
mucosa,  almost  always  by  bites  or  scratches. 

5.  Portal  oj  Entrance. — Through  the  subcutaneous  tissue  to 
the  terminal  nerve  fibers. 

6.  Incubation  Period. — Variable,  seldom  less  than  four  weeks 
and  occassionally  six  months  or  longer. 

7.  Period  oj  Communicability. — For  perhaps  two  weeks  prior 
to  the  manifestation  of  symptoms  and  throughout  the  clinical 
course  of  the  disease. 

8.  Methods  of  Control. — (a)  Diagnosis  (in  animals). — Clini- 
cal manifestations  of  animals,  confirmed  by  the  rinding  of  Negri 
bodies  in  the  brain,  or  by  successful  animal  inoculations  with 
such  a  brain. 

(b)  Isolation  (of  Patient). — None,  if  patient  is  under  adequate 
medical  supervision  and  the  immediate  attendants  are  warned 
of  the  possibility  of  inoculation  by  human  virus. 

Animals  which  are  suspected  of  being  rabid  and  which  have 
bitten  or  exposed  a  person  to  infection,  should  not  be  killed, 
inasmuch  as  the  laboratory  confirmation  of  the  suspected  diag- 
nosis may  be  rendered  difficult  or  time  consuming.  Such  ani- 
mals should  be  confined  in  rigid  isolation  and  closely  observed. 
If  actually  rabid,  death  will  occur  within  ten  days  and  the 
diagnosis  can  be  confirmed  by  the  clinical  course  and  labora- 
tory examination.  If  the  animal  is  alive  at  the  end  of  this 
period  the  question  of  rabies  is  eliminated.  This  precaution 
does  not  endanger  the  patient  through  too  great  delay  in  be- 
ginning the  Pasteur  treatment. 

(c)  Immunization. — The  administration  of  active  immuniza- 
tion (Pasteur  treatment)  after  exposure  to  infection  by 
inoculation.  The  Pasteur  treatment  should  be  administered 
under  the  following  circumstances: 

A.  From  a  diagnosis  of  rabies  in  the  biting  animal  based  on 
one  or  more  of  the  lollowing  data:  (1)  Clinical  manifestations, 
(2)  Negri  bodies,  (3)  Inoculation,  or, 

B.  On  suspicion,  where  the  biting  animal  is  at  large  but 
manifested  suspicious  symptoms. 


LOWER   ANIMALS    AS    SOURCES    OF   INFECTION   FOR   MAN  213 

Various  methods  have  been  devised  for  the  attenuation  of 
the  rabies  virus,  but  those  is  most  general  use  closely  follow  the 
technique  developed  by  Pasteur.  The  rabic  virus  derived  from 
carnivorae  is  attenuated  for  man  by  successive  passages  through 
rabbits,  until  its  incubation  period  becomes  constant.  It  is  then 
known  as  fixed  virus,  and  has  an  incubation  period  of  six  to 
seven  days  when  inoculated  intracerebrally  into  rabbits.  The 
spinal  cord  of  a  rabbit  dying  of  fixed  virus  infection  is  asepti- 
cally  removed  intact  and  dessicated  in  a  jar  over  sticks  of 
caustic  soda,  producing  a  further  attenuation.  From  day  to 
day,  up  to  the  8th  day  of  dessication,  pieces  of  dried  cord  repre- 
senting about  1  cm.  of  the  fresh  cord  are  removed  to  glycerine 
and  designated  as  one,  two  or  three  day  cord,  etc.,  according 
to  the  extent  of  the  dessication  to  which  they  have  been  sub- 
jected. Under  refrigeration,  these  remain  potent  about  one 
month. 

For  administration  the  dried  cord  is  further  prepared  as 
follows:  A  piece  of  the  dried  cord  is  washed  in  saline  to  remove 
the  glycerine,  and  ground  in  a  small  mortar  until  homogenous. 
Then  drop  by  drop  two  and  five  tenths  c.c.  of  saline  are  added 
and  thoroughly  mixed  with  the  cord  until  a  homogenous  sus- 

SCHEMA    OF    THE    PASTEUR    TREATMENT 


Day  of  treatment 

Age  of  dried  cord 

Amount  injected 

I 

8-7-6 

2-5 

2 

4-3 

2-5 

3 

5-4 

2-5 

4 

3 

2-5 

5 

3 

2-5 

6 

2 

2-5 

7 

2 

2-5 

8 

1 

2-5 

9 

5 

2.5 

10 

4 

3-5 

11 

4 

2-5 

12 

3 

2-5 

13 

3 

2-5 

14 

2 

2-5 

IS 

2 

2-5 

16 

4 

2-5 

17 

3 

2-5 

18 

2 

2.5 

19 

2 

2-5 

20 

3 

2-5 

21 

2 

2.5 

For  children  the  doses  of  the  stronger  viruses  are  reduced. 


214 


PRACTICAL   PREVENTIVE   MEDICINE 


pension  is  secured.  This  is  the  material  for  injection.  The  site 
of  election  is  the  subcutaneous  tissue  of  the  abdominal  wall, 
which  is  prepared  by  painting  the  skin  with  iodine. 

With  the  vaccine  distributed  bythe  U.  S.  P.  H.  S.,  the  course 
of  treatment  covers  twenty  five  injections  given  over  a  period 
of  twenty  one  days.  The  schedule  followed  in  the  intensive 
treatment  of  adults  is  as  given  in  the  preceding  table. 

(d)  Quarantine. — Of  dogs  transported  from  infected  to  unin- 
fected areas  for  six  months. 

(e)  Concurrent  Disinfection. — Of  patient's  saliva  and  objects 
contaminated  therewith. 


Pig.   92. — Proper  and  improper  muzzling  of  dogs.     The  muzzle  on  the  right 
hand  dog  is  ineffective,  as  it  may  be  easily  slipped  from  position.      (U.  S.  P.  H.  S.) 


if)  Terminal  Disinfection. — Thorough  cleaning. 
General  Measures. — {a)  Muzzling  of  dogs  when  on  public 
streets  or  in  places  to  which  the  public  has  access   (Fig.  92). 

(b)  Detention  and  examination  of  dogs  suspected  of  having 
rabies.  Detention  should  be  maintained  ten  days.  If  death 
occurs  search  should  be  made  for  Negri  bodies. 

(c)  Provision  for  the  immediate  anti-rabic  treatment  (active 
immunization)  of  persons  bitten  by  dogs  or  other  animals 
suspected  or  known  to  have  rabies.  The  wounds  should  be 
cauterized  with  fuming  nitric  acid  as  soon  after  their  infliction 
as  possible. 


LOWER   ANIMALS    AS    SOURCES    OF   INFECTION   FOR   MAN  215 

ANTHRAX 

i.  Infective   Agent. — Bacillus    anthracis. 

2.  Sources  oj  Injection. — Cases  in  cattle,  sheep  and  horses. 

3.  Portal  oj  Exit. — In  extra vasated  blood. 

4.  Route  oj  Transmission. — By  the  hair,  hides  and  feces  of 
infected  animals  or  objects  such  as  soil  or  dust,  contaminated 
therewith.  It  must  be  borne  in  mind  that  this  is  a  spore 
forming  organism  which  can  survive  the  action  of  sunlight  and 
desiccation  for  prolonged  and  indefinite  periods,  such  as  months 
and  years.  Hence  contaminated  intermediate  objects  may 
serve  as  fomites. 

5.  Portal  of  Entrance. — By  inoculation  of  the  spores  into  the 
subcutaneous  tissues  by  scratches,  wounds  or  the  inhalation  of 
spores  in  dust. 

6.  Incubation  Period. — Within  seven  days. 

7.  Period  of  Communicability. — During  the  febrile  stage 
and  until  the  lesions  have  ceased  discharging.  Infected  hair 
and  hides  of  infected  animals  may  communicate  the  disease 
for  many  months  after  the  slaughter  or  skinning  of  the  animals, 
and  even  after  the  curing  of  the  hide  or  hair,  unless  previously 
disinfected. 

8.  Methods  of  Control.  The  Infected  Individual. — (a)  Di- 
agnosis: Clinical  manifestations  confirmed  by  bacteriological 
examination. 

(b)  Isolation:  Until  the  lesions  have  healed. 

(c)  Immunization:  No  highly  effective  method  for  the 
immunization  of  man  has  been  developed.  The  anti-anthrax 
serum  is  well  worth  a  trial.  Normal  beef  serum  is  said  to 
give  good  results. 

(d)  Quarantine:  None. 

(e)  Concurrent  Disinfection:  Of  the  discharges  from  the 
lesions  and  of  objects  soiled  therewith. 

(0  Terminal  Disinfection:  Thorough  cleaning. 

General  Measures. — {a)  Animals  ill  with  a  disease  presum- 
ably anthrax  should  be  placed  immediately  in  the  care  of  a 
veterinarian.  Proved  cases  should  be  promptly  killed  and 
the  carcass  destroyed  by  cremation. 

(b)  Isolation:  Only  of  suspected  cases. 

(c)  Active  Immunization:  Of  exposed  animals  under  govern- 
mental supervision.  The  double  vaccine,  consisting  of  two 
separate  inoculations  with  doses  of  graded  virulence,  is  in  most 
general  use. 


2l6 


PRACTICAL   PREVENTIVE   MEDICINE 


(d)  Post  mortem  examinations  should  be  made  only  by  a 
veterinarian  or  bacteriologist. 

(e)  Milk  from  an  infected  animal  should  not  be  used. 

(/)  Control  of  and  the  disinfection  of  sewage  effluents  and 
trade  wastes  from  factories  and  premises  where  spore  infected 
hides  or  hair  are  known  to  have  been  worked  up  into  manu- 
factured articles. 

(g)  A  physician  should  be  employed  by  every  company  hand- 
ling raw  hides  or  hair,  or  else  such  companies  should  operate 


Fig.  93. — Wool  sorting.      In  wool  manufacturing  centers  occupational  anthrax 
is  commonly  known  as  "wool-sorters'  disease."      (Bull.  205,  Bur.  Lab.  Stat.) 

under  the  direct  supervision  of  a  medical  representative  of  the 
health  department. 

(k)  Every  employee  handling  raw  hides,  hair  or  bristles  who 
has  an  abrasion  of  the  skin  should  immediately  report  to  a 
physician. 

(i)  All  employees  in  such  establishments  should  be  personally 
instructed  in  the  necessity  for  personal  cleanliness. 

(j)  Tanneries  and  woolen  mills  should  be  provided  with 
proper  ventilating  apparatus  so  that  dust  can  be  promptly 
removed. 

(k)  All  hair,  wool,  and  bristles  originating  in  known  infected 


LOWER   ANIMALS    AS    SOURCES    OF   INFECTION   FOR   MAN  217 

centers  should  be  disinfected  before  they  are  cured  or  sorted 
(Fig.  93). 

(/)  The  sale  of  hides  from  animals  dying  from  anthrax  should 
be  prohibited. 

(m)  Hides  of  unknown  origin  should  be  disinfected.  Means 
of  disinfection  that  will  not  interfere  with  the  desirable  proper- 
ties of  leather  are  not  available.  The  following  is  the  least 
objectionable  method: 

Immerse  the  hides  in  i  per  cent,  hydrochloric  acid  and  8  per 
cent,  sodium  chloride  for  6  hours  at  a  temperature  of  40°C. 
Then  neutralize  with  sodium  carbonate  and  wash. 

(n)  Workmen  should  be  instructed  to  avoid  touching  blood 
clots  on  hides  or  hair. 

TETANUS 

i.  Infective  Agent. — Bacillus  tetani. 

2.  Source  of  Infection. — Herbivorous  animals,  particularly 
horses  and  mules. 

3.  Portals  of  Exit. — The  feces  of  such  animals,  rarely  the  dis- 
charge from  infected  wounds. 

4.  Route  of  Transmission. — Animal  manure  and  objects  and 
soil  contaminated  with  animal  manure.  The  spores  of  the 
organisms  are  very  resistant  and  can  survive  for  indefinite 
periods  outside  the  body.     Hence  fomites  transmission  occurs. 

5.  Portal  of  Entrance. — Subcutaneous  introduction  of  spores 
into  wounds,  cuts  and  abrasions,  usually  through  their  con- 
tamination with  soil  or  manure,  hair,  etc. 

6.  Incubation  Period. — Six  to  fourteen  days,  usually  nine. 

7.  Period  of  Communicability . — The  patient  is  not  a  source 
of  infection,  except  in  rare  cases  where  the  wound  discharges 
are  infective.  On  the  other  hand,  some  horses  are  chronic 
carriers. 

8.  Methods  of  Control.  The  Infected  Individual. — (a)  Diag- 
nosis: Clinical  manifestations  which  may  sometimes  be  con- 
firmed bacteriologically. 

(b)  Isolation:  None. 

(c)  Immunization:  Passive  protection,  secured  by  the  ad- 
ministration of  antitoxin,  should  be  employed.  The  antitoxin 
has  given  the  best  results  as  a  prophylactic  agent.  As  a  result 
of  recent  military  experience  the  folllwing  rules  should  be  fol- 
lowed in  its  administration: 

1.  Every  wounded  person  should  receive  at  least  500  units 


2l8  PRACTICAL  PREVENTIVE  MEDICINE 

prophylactically.     This  dose  should  be  repeated  on  the  7th  and 
14th  days  thereafter. 

2.  Repeat  the  doses  at  more  frequent  intervals  if  there  is 
any  reason  to  fear  tetanus. 

3.  Repeat  injections  forty  eight  hours  prior  to  any  secondary 
operation. 

4.  If  tetanic  manifestations  develope,  the  subcutaneous  and 
intramuscular  routes  of  injection  are  preferable.  Daily  doses 
of  at  least  10,000  units  should  be  given  and  continued  well  into 
convalescence.  The  injections  should  be  given  at  different 
depths  and  at  several  points  in  the  muscle  tissue  on  the  injured 
side,  if  an  operation  is  contemplated. 

The  importance  of  early  prophylactic  doses  is  indicated  by 
the  following  results  in  65  cases  of  tetanus: 

(a)  Antitoxin  administered  within  24  hrs.  of  wounding:  43 
cases,  each  receiving  500  units;  62.7  per  cent,  fatal,  37.2  per 
cent,  recovered. 

(b)  Antitoxin  administered  after  24  hrs.  of  wounding:  23 
cases,  each  receiving  500  units;  86.9  per  cent,  fatal,  13. 1  per 
cent,  recovered. 

(d)  Quarantine:  None. 

(e)  Concurrent  Disinfection:  None. 
(/)  Terminal  Disinfection:  None. 

General  Measures  (Especially  to  Prevent  Wound  Contamination) . 
(a)  Supervision  of  the  practice  of  obstetrics,  so  that  proper 
care  is  given  to  the  care  of  the  infant's  cord  (Trismus 
neonatorum). 

(b)  Educational  propaganda,  along  the  lines  of  the  "safety 
first"  campaigns  and  "Safe  and  Sane"  Fourth  of  July 
campaigns. 

(c)  Prophylactic  use  of  tetanus  antitoxin  when  wounds  have 
been  acquired  in  regions  where  the  soil  is  known  to  be  heavily 
contaminated  with  manure,  and  in  all  cases  whose  wounds  are 
ragged  and  penetrating. 

(d)  Removal  of  all  foreign  matter  from  wounds  as  early  as 
possible. 

(e)  Governmental  supervision  of  biological  products,  so  that 
only  potent  antitoxin  is  distributed. 

REFERENCES 

The  Rat  and  its  Relation  to  Public  Health.     U.S.P.H.S. 
Anthrax   as  an  Occupational   Disease.     Bull.    205,   U.   S.  Bureau  of  Labor 
Statistics. 


LOWER   ANIMALS    AS    SOURCES    OF   INFECTION   FOE    MAN  219 

Outbreak   and   Suppression   of   Plague  in  Porto  Rico.     Reprint  130,  Public 

Health  Reports. 
Plague,    its    Geographic    Distribution    and    Menace   to   the   United    States. 

Reprint  130,  Public  Health  Reports. 
Rat    Proofing    the    Public    Docks    of    New    Orleans.     Reprint   259,    Public 

Health  Reports. 
Rat  Proofing'  and  its  Practical  Application  to  the  Construction  and  Repair 

of  Dwellings  and  Other  Buildings.     Reprint  122,  Public  Health  Reports. 
Rocky  Mountain  Spotted  Fever:  A  report  of  its  investigation  and  of  meas- 
ures  undertaken  for  its   eradication   during    1914.     Reprint    251,    Public 

Health  Reports. 
Facts  and  Problems  of  Rabies.     Bull.  65,  Hygienic  Lab.  U.S.P.H.S. 
Investigations   of,  and  Tick  Eradication  in  Rocky  Mountain  Spotted  Fever. 

Reprint  79,  Public  Health  Reports. 
The   Eradication  and   Prevention  of   Bubonic  Plague.     Reprint  88,  Public 

Health  Reports. 
Technique   of   the  Laboratory   Examination  of   Rats  for  Plague.     Reprint 

89,  Public  Health  Reports. 
Post   Mortem    Diagnosis   of   Plague.     Reprint   90,   Public  Health  Reports. 
Rocky  Mountain  Spotted  Fever.     Reprint  96,  Public  Health  Reports. 
A  Squirrel  Destructor.     Reprint  98,  Public  Health  Reports. 
Bubonic    Plague:    its   eradication   and    prevention   in    urban    communities. 

Reprint  209,  Public  Health  Reports. 
Post-vaccination  Tetanus.     Reprint  289,  Public  Health  Reports. 
How  to  poi-son  rats.     Public  Health  Reports,  Aug.,  191 2. 


CHAPTER  XXIII 
OTHER  ASPECTS  OF  INFECTIOUS  DISEASE 

i.  In  the  foregoing  chapters  we  have  considered  a  number  of 
the  infectious  diseases  of  public  health  importance  in  the 
United  States.  These  for  the  most  part  are  diseases  which  are 
systemic  in  character  and  the  losses  we  have  considered  have 
been  direct  losses  either  from  sickness  or  death.  There  is 
another  type  of  damage  which  these  diseases  may  produce 
that  is  fully  as  important  as  the  losses  we  have  heretofore  con- 
sidered, namely  the  sequelae.  These  consist  of  a  permanent 
injury  or  impairment  of  function  arising  from  the  illness,  as  a 
consequence  of  which  the  individual  may  never  be  restored  to 
the  degree  of  physical  efficiency  existing  before  the  illness, 
and  while  he  may  recover  from  the  infection,  the  permanent 
damage  may  either  assist  in  the  development  of  other  patho- 
logical processes  which  shorten  life  or  reduce  the  economic 
efficiency  of  the  individual.  We  will  briefly  consider  the 
injuries  of  this  character.  But  little  quantitative  data  on  this 
point  are  available,  so  the  presentation  will  deal  necessarily 
with  generalities. 

In  a  study  of  nearly  two  thousand  cases  of  typhoid  fever, 
Dublin  finds  that  cardiac  disease  and  a  lowered  resistance  to 
tuberculosis  are  the  most  important  sequelae  manifesting  their 
effect  within  three  years  following  recovery.  He  concludes 
that  during  this  period  the  mortality  is  twice  that  among  in- 
dividuals who  have  not  had  typhoid  fever.  It  is  usually  con- 
sidered that  with  typhoid,  ten  per  cent,  of  the  cases  have  a 
fatal  outcome.  He  points  out  that  in  addition,  the  sequelae 
which  produce  a  fatal  outcome  increase  this  mortality  very 
nearly  by  five  per  cent.  The  fact  that  an  increased  mortality 
from  tuberculosis  is  observed  is  very  important.  Many  of  the 
acute  infections  so  undermine  the  individual's  resistance  to  a 
more  chronic  infection  such  as  tuberculosis,  to  an  extent  that  a 
heretofore  latent  infection  becomes  active  or  the  nephritis 
appearing  as  a  complication  of  scarlet  fever  may  fail  to  clear  up 
with  convalescence,  and  remain  as  a  permanent  injury  to  the 
individual.     Diphtheria    toxin    may  permanently  impair    the 


OTHER    ASPECTS    OF    INFECTIOUS    DISEASE  221 

nervous  system,  so  that  the  post-diphtheritic  paralyses  are  one 
of  the  most  dreaded  sequelae  of  any  disease.  Likewise  the  great 
popular  horror  of  poliomyelitis  arises  from  the  disabling  paral- 
ysis so  common  in  those  who  recover.  The  greatest  progress 
we  have  made  with  poliomyelitis  in  recent  years  has  been  in  the 
intelligent  orthopedic  handling  of  these  cases.  The  results  are 
so  striking  and  so  beneficial  that  many  progressive  state  health 
authorities  are  now  following  up  all  poliomyelitis  cases  and 
making  provision  for  orthopedic  relief.  Similar  disablement 
may  follow  cerebrospinal  meningitis,  together  with  deafness. 
Noticeable  mental  or  nervous  impairment  may  follow  typhus 
fever  or  whooping  cough.  Gonorrheal  infection  of  the  geni- 
talia in  either  male  or  female  is  frequently  responsible  for  sub- 
sequent sterility  of  the  individuals,  and  where  infection  is 
transferred  to  the  eye,  permanent  blindness  may  result.  After 
the  active  infective  stages  of  syphilis  are  past  the  individual 
may  suffer  great  physical  disability  from  the  lesions  of  the 
tertiary  and  quaternary  stages.  It  is  therefore  apparent  that 
the  ravages  of  those  diseases  are  not  sufficiently  brought  out 
by  a  study  of  the  mortality  or  morbidity  records  alone. 

Another  aspect  of  this  subject  is  that  of  the  so-called  "  focal 
infections"  whose  importance  was  first  emphasized  by  Billings 
and  his  associates.  Chronic  infection  localized  in  some  ob- 
scure area  of  the  body  may  be  responsible  for  the  production 
of  acute  rheumatism,  chronic  deforming  arthritis,  gonorrheal 
arthritis,  malignant  endocarditis,  myositis,  myocarditis,  sep- 
ticemias of  several  types,  certain  infectious  types  of  thyroiditis 
with  or  without  hyperthyroidism,  acute  and  chronic  pancreatitis 
with  or  without  glycosuria,  gastric  ulcer  and  cholecystitis. 
The  situations  in  which  the  chronic  infection  is  localized  are 
most  commonly  the  dental  alveoli,  the  tonsils,  the  gall  bladder, 
the  appendix  or  a  nasal  sinus.  From  these  locations  bacterial 
emboli  are  thrown  off  into  the  circulation,  and  if  the  defenses  of 
the  body  are  diminished  by  overwork,  exposure  to  cold,  dissipa- 
tion, insufficient  or  improper  food,  unhygienic  surroundings, 
injuries  from  former  diseases  (valvular  scars)  or  trauma,  some 
of  the  conditions  mentioned  may  develop.  The  responsible 
micro-organisms  are  most  commonly  those  of  the  pneumococcus- 
streptococcus  group.  From  a  public  health  standpoint  these 
conditions  do  not  come  to  the  attention  of  the  health  authorities 
except  in  so  far  as  they  participate  in  mortality  production. 
But  from  the  standpoint  of  the  practising  physician  they  are  a 
field  of  preventive  medicine  in  which  brilliant  results  may  be 


2  22  PRACTICAL  PREVENTIVE  MEDICINE 

secured  by  searching  for  the  chronic  focus  of  infection  and 
effecting  its  removal. 

Disease  prevention  by  the  developement  of  an  active  arti- 
ficial immunization  against  the  infective  agent  concerned, 
among  all  susceptibles  in  a  given  population,  is  our  chief 
weapon  in  the  control  of  certain  infections  such  as  small- 
pox, and  a  valuable  adjunct  in  others.  The  maximum  effi- 
ciency of  such  measures  is  only  achieved  where  immunization 
is  made  compulsory  and  where  furthermore,  the  requirement 
is  enforced,  so  that  a  large  part  if  not  ali  the  people  are  pro- 
tected Unfortunately  in  civil  life,  compulsory  vaccination  has 
lead  to  a  greater  or  less  amount  of  opposition  among  a  few 
bigoted  persons  who  fortify  their  position  by  refering  to  the 
very  small  number  of  accidents  and  secondary  infections  fol- 
lowing the  practice,  and  ignore  the  achievements  in  disease 
reduction  that  has  followed  the  extensive  employment  of  the 
method.  This  opposition  in  some  localities  has  been  so  vigo- 
rous that  authorities  have  been  unable  to  enforce  the  provisions 
of  laws  requiring  compulsory  vaccination  while  in  others  the 
authorities  are  forced  into  a  continuous  fight  to  prevent  the 
repeal  of  the  statutory  requirements.  In  many  localities  the 
situation  is  discouraging.  Fortunately  the  situation  has  a 
redeeming  feature.  Those  who  receive  immunization  receive 
protection,  while  those  who  do  not,  either  through  ignorance, 
carelessness  or  opposition  run  the  far  greater  hazard  of  the 
virulent  infection.  Those  who  remain  unvaccinated  through 
opposition  are  sufficiently  punished  if  they  contact  infection. 
Health  authorities  can  in  a  large  measure  protect  the  individuals 
of  the  other  groups  by  education  of  the  public  in  the  advan- 
tages of  vaccination,  by  the  distribution  of  free  vaccine,  and 
by  providing  for  its  free  administration.  Sufficient  activity 
along  these  lines  may  very  nearly  achieve  the  same  results  as 
compulsory  methods,  without  arousing  hampering  opposition. 
Practicing  physicians  can  do  a  great  deal  in  disease  prevention 
by  actively  immunizing  their  clientel. 

REFERENCES 

Dublin:  Typhoid  Fever  and  its  Sequelae.  American  Journal  Public 
Health,  V,  pp.  20,  1915. 

Billings:  Focal  Infection:  its  broader  application  in  the  etiology  of  general 
disease.     Journal  Amer.  Medical  Association  LXIII,  899,  1914. 


SECTION  II 
DEFICIENCY  DISEASES 

CHAPTER  XXIV 
FOOD    REQUIREMENTS:    PRODUCTION    AND    RETAIL 

i  The  activities  of  the  cellular  tissues  of  the  body  require 
that  the  necessary  material  for  growth,  for  renewal  of  the  worn 
tissues  and  for  energy  be  supplied.  This  material  constitutes 
food  From  it  the  body  liberates  the  necessary  energy  and 
secures  new  material  for  replacement  purposes.  Cellular 
activity  is  in  different  directions  and  for  each  type  of  activity 
different  raw  materials  must  be  furnished.  The  most  impor- 
tant raw  materials  which  the  body  requires  are  protein  food 
and  certain  mineral  salts.  The  importance  of  protein  arises 
from  its  nitrogenous  content  and  hence  it  serves  chiefly  in  repair 
and  new  growth,  and  to  a  lesser  extent  as  a  source  of  energy. 
The  energy  requirements  are  chiefly  met  by  carbonaceous  foods. 
The  mineral  salts  are  required  to  maintain  tonicity  of  the  body 
fluids,  to  build  up  the  solid  tissues,  to  form  hemoglobin  and  tor 
other  purposes.  . 

The  determination  of  the  value  of  any  given  substance  as  a 
food  is  not  a  simple  matter.  Several  different  aspects  must  be 
considered.  First  perhaps,  must  be  considered  the  percentage 
chemical  composition  of  the  substance.  It  must  be  assayed  to 
determine  its  value  in  terms  of  food  constituents,  such  as  pro- 
tein, carbohydrates,  fats  and  inert  material.  A  second  test  to 
determine  suitability  is  of  a  physical  character,  and  enables  us  to 
judge  the  value  of  the  food  stuff  as  a  fuel  or  source  of  energy. 
It  is  usually  calculated  from  the  results  of  the  chemical  analysis 
by  the  employment  of  the  following  factors,  and  is  expressed 
in  calories: 

i  gm.  of  protein  will  produce 4- 1  calories 

i  gm.  of  carbohydrate  will  produce    41  calories 

1  gm.  of  fat  will  produce 9-3  calories 

223 


224  PRACTICAL   PREVENTIVE   MEDICINE 

However,  since  different  food  stuffs  are  not  consumed  in  the 
body  to  the  same  degree,  those  factors  will  not  always  give  an 
accurate  idea  of  the  value  of  a  food  as  fuel.  Next  one  must 
consider  the  food  stuff  from  the  body's  standpoint.  It  must 
be  one  which  is  capable  of  digestion  and  absorption  by  the  body, 
and  of  meeting  the  body's  needs.  Different  individuals  are 
capable  of  utilizing  different  materials  to  different  degrees. 
In  general  92.6  per  cent,  of  protein;  94.4  per  cent,  of  carbohy- 
drate and  97  per  cent,  of  fat  are  absorbed.  Some  few,  such  as 
sugar  are  practically  entirely  absorbed.  A  fourth  and  equally 
as  important  guide  to  judgment  is  the  knowledge  whether  a 
given  food  stuff  can  be  obtained  at  a  reasonable  cost. 

In  general  the  following  represents  what  may  be  considered 
a  standard  in  the  United  States  for  the  proportion  in  which  the 
different  food  elements  should  be  represented  in  the  diet  of 
adults  each  day. 

Protein 125  gms.  X  4 . 1  =     512.5  calories 

Carbohydrates....   400  gms.  X  4.1  =  1640.     calories 
Fat 125  gms.  X  9.3  =  1161.5  calories 

Some  variation  in  these  proportions  can  be  made  without  in- 
jury but  a  certain  amount  of  protein  is  absolutely  necessary, 
though  the  exact  limit  is  not  known.  A  further  important 
factor  in  considering  the  protein  element  is  whether  its  content 
of  amino  acids  is  of  the  one  or  more  types  which  the  body  can 
rebuild  into  its  own  protein.  If  the  amino  acids  are  unsuitable, 
the  protein  present  is  useless. 

Of  the  food  consumed,  less  than  one-sixth  furnishes  energy 
for  work,  the  balance  being  lost  as  heat.  In  this  respect  the 
body's  requirements  and  use  of  food  are  similar  to  the  fuel 
consumption  of  an  engine.  Similarly  more  work  requires  more 
food.  An  average  adult  male  of  150  pounds  weight  engaged 
different  activities  has  approximately  the  following  daily  fuel 
requirements: 

Resting  in  bed 2000  calories 

Resting  in  a  chair 2230  calories 

Light  work 2600  calories 

Moderate  muscular  work 3100  calories 

Severe  muscular  work 35°o  calories 

The  energy  for  the  extra  work  is  chiefly  supplied  by  the  car- 
bonaceous foods. 

2.  Food  is  essential  to  life  and  because  of  this  requirement, 


FOOD    REQUIREMENTS,    PRODUCTION   AND    RETAIL  225 

food  production  everywhere  is  a  fundamental  industry  and 
is  the  principal  basis  of  agricultural  pursuits.  From  the 
standpoint  of  raw  materials  or  source,  food  stuffs  are  either 
animal  or  vegetable  in  origin.  From  a  hygienic  standpoint, 
the  animal  foods  are  of  greater  importance  than  the  vegetable, 
as  has  been  shown  in  Chapter  XIX.  With  the  animal  foods 
we  can  group  meat,  fowl,  fish,  shellfish,  crustaceans,  insects 
and  their  products,  eggs,  milk  and  dairy  products,  animal  fats 
and  gelatine.  The  vegetable  foods  comprise  cereals,  vegetables 
proper,  fruits,  sugar,  gums,  vegetable  oils  and  fats.  While  the 
production  of  these  food  stuffs  is  the  basis  of  agriculture  and 
fishing  pursuits,  yet  many  as  produced  are  not  suitable  for  im- 
mediate use  as  food,  or  if  suitable  they  require  treatment  to 
remove  bulky,  inert,  and  useless  material,  or  to  preserve  them 
suitably  for  transportation.  Around  these  processes  have  grown 
up  a  host  of  secondary  industries.  It  is  apparent  therefore  that 
industries  based  upon  food  stuffs  are  at  the  foundation  of  our 
economic  life,  as  the  need  for  food  is  at  the  foundation  of  our 
physical  life. 

3.  In  connection  with  the  handling  of  food  stuffs,  and  the 
development  of  various  technical  processes  in  their  treatment, 
certain  practices  arose,  many  of  which  were  fraudulent  in  char- 
acter and  a  few  perhaps  inimical  to  health,  which  the  Federal 
and  State  governments  have  endeavored  to  suppress  by  means 
of  the  so-called  Pure  Food  Legislation.  These  objectionable 
practises  are  commonly  known  as  adulterations  and  according 
to  most  legislation  are  classified  as  follows: 

(a)  Mixing  the  material  with  foreign  substances  to  reduce 
or  lower,  or  injuriously  affect  the  quality  or  strength,  as  for 
example  the  mixing  of  water  with  milk. 

(b)  The  substitution  of  one  substance  for  another,  either 
wholly  or  in  part,  such  as  the  employment  of  cotton  seed  oil  for 
olive  oil. 

(c)  The  removal  of  any  valuable  constituent  either  wholly 
or  in  part,  as  for  example  the  skimming  of  cream  from  milk. 

(d)  The  treatment  of  the  food  stuff  to  conceal  damage  or 
inferiority,  as  for  example  the  addition  of  sulphites  to  old  meat 
to  give  it  a  bright  red  color. 

(e)  The  presence  of  added  deleterious  ingredients,  injurious 
to  health.  The  so-called  chemical  preservatives  come  under 
this  head,  such  as  borax  or  formalin. 

(/)  Or  the  retail  of  food  stuffs  that  are  wholly  or  in  part  de- 
composed, filthy,  or  putrid. 
15 


226  PRACTICAL    PREVENTIVE    MEDICINE 

It  can  readily  be  seen  that  for  the  most  part  the  practices 
grouped  here  deal  practically  with  the  cheating  of  the  purchaser 
or  consumer  by  unscrupulous  dealers,  and  as  such  more  directly 
affect  the  pocket  book  than  it  does  health. 

4.  Most  food  stuffs  are  as  well  adapted  to  the  needs  of  various 
other  forms  of  life  as  they  are  to  man's,  particularly  to  micro- 
organisms. As  a  consequence  of  the  activity  of  these,  most  food 
stuffs  readily  spoil  or  undergo  decomposition.  One  of  the 
greatest  forward  steps  in  our  economic  progress  has  been  the  dis- 
covery and  application  of  means  whereby  decomposition  may 
be  prevented.  Thus  seasonable  and  perishable  foods  may  be 
kept  from  years  of  plenty  to  years  of  scarcity,  perishable  foods 
may  be  transported  to  distant  markets,  and  dense  concen- 
trations of  population  at  a  great  distance  from  their  source 
of  food  supply  are  possible.  The  great  cities  of  our  day 
have  developed  progressively  with  the  development  of  food 
preservation. 

The  object  of  food  preservation  is  to  preserve  the  nutritive 
value  of  the  food  stuffs  and  their  palatability  for  an  indefinite 
period  and  at  least  until  the  next  season.  Food  stuffs  designed 
for  preservation  should  be  fresh  and  wholesome  in  their  raw 
state.  The  methods  of  preservation  are  all  designed  to  inhibit 
the  activity  of  the  micro-organisms  which  produce  the  changes 
of  decomposition.  Among  these  we  may  mention  refrigeration 
and  freezing,  drying,  salting,  smoking,  canning  by  the  aid  of 
heat  (sterilization),  preserving  by  the  use  of  strong  sugar  solu- 
tions, and  the  use  of  antiseptic  chemicals,  such  as  vinegar  and 
spices. 

5.  Of  equal  if  not  of  greater  importance  with  production  from 
a  hygienic  aspect,  are  the  conditions  of  retail  sale  and  consump- 
tion of  food  stuffs,  particularly  from  the  standpoint  of  the 
transmission  of  infective  agents.  Food  stuffs  on  the  retail 
market  are  as  a  rule  but  a  few  hours  away  from  their  consump- 
tion, so  that  if  contaminated  with  infective  agents  the  chances 
for  the  survival  of  the  latter  and  their  successful  invasion  of 
the  consumer  are  excellent.  From  an  esthetic  standpoint, 
the  physical  appearance  of  a  retailer's  wares  influences  the 
purchases  a  customer  will  make.  The  two  conditions  we  have 
mentioned  are  affected  by  the  character  of  the  retail  establish- 
ment, its  cleanliness,  the  number  and  variety  of  vermin  present 
and  whether  food  stuffs  are  protected  from  vermin  as  well  as 
unnecessary  handling  by  both  clerks  and  prospective  customers. 
And  in  this  connection  restaurants  are  of  equal  if  not  greater 


FOOD  REQUIREMENTS,  PRODUCTION  AND  RETAIL     227 


importance  than  retail  stores.  Clerks,  waiters,  cooks,  dish- 
washers, etc.,  may  be  typhoid  carriers  or  in  the  active  infective 
stage  of  venereal  disease  or  other  infection;  or  the  knives, 
forks,  spoons,  plates,  cups,  etc.  of  eating  houses  may  not  be 
adequately  cleansed  between  the  services  they  render  to  suc- 
cessive patrons,  so  that  infective  agents  survive  upon  them. 
In  this  capacity  soft  drink  stands  are  of  great  importance.  The 
ordinary  methods  of  washing  dishes,  glassware  and  eating 
utensils  employed  in  restaurants  and  eating  houses  are  insuffi- 
cient to  destroy  infective  agents  present  in  the  buccal  secretions 
with    which    they    are  contaminated  after  use.     Furthermore 


FlG.  94. — Dish-washing — a   simple,    efficient   method   of   sterilizing   the   dishes 
{Overton  and  Denno,  "  The  Health  Officer.") 

they  serve  to  distribute  these  over  all  other  dishes  which  are 
being  washed  at  the  same  time.  The  use  of  boiling  water  is 
the  most  practical  method  for  effecting  this  sterilization.  The 
dishes,  etc.,  are  given  a  preliminary  cleaning  in  hot  water  sup- 
plemented with  soap,  or  in  soap  suds,  and  then  placed  in  a 
wire  basket,  which  is  dipped  into  a  large  kettle  of  boiling  water 
kept  constantly  available  for  this  purpose.  This  method  of 
handling  dishes  possesses  the  additional  advantage  that  no 
subsequent  wiping  is  necessary.  Or  in  the  retail  stores,  food- 
stuffs many  of  which  are  ordinarily  eaten  without  further 
heating  or  cooking,  are  exposed  to  flies,  roaches,  rats,  mice, 


228  PRACTICAL   PREVENTIVE    MEDICINE 

dogs,  or  the  fingers  of  prospective  customers.  Thus  their  con- 
tamination with  infective  secretions  may  occur  and  infective 
agents  upon  them  stand  an  excellent  chance  of  reaching  a  new- 
host.  Employees  who  have  cases  of  diseases  transmitted  by 
contact  in  their  families  should  be  excluded  from  employment 
until  it  is  ascertained  they  are  free  from  infection  and  that  they 
subsequently  remain  away  from  their  infected  household  during 
its  quarantine. 


CHAPTER  XXV 
DISEASES  DUE  TO  DIETARY  DEFICIENCIES 

RELATION  OF  FOOD  TO  HEALTH 

The  quantity  of  food  required  to  maintain  the  body  in  vigor 
varies  with  the  climate  and  season,  clothing,  occupation,  work 
and  exercise,  the  state  of  individual  health,  age,  sex,  and  body 
weight.  Modern  conditions  of  food  preparation  frequently 
stimulate  the  appetite  so  that  one  consumes  food  far  in  excess 
of  the  body's  requirements.  When  coupled  with  insufficient 
exercise  the  results  are  bad.  When  prolonged  it  may  lead  to 
such  diatheses  as  obesity  and  gout,  and  even  though  these 
conditions  may  not  be  produced,  the  temporary  effects,  the 
congestion  of  the  digestive  tract,  the  intestinal  stasis,  all  exert 
a  reflex  action  upon  the  central  nervous  system  with  the  pro- 
duction of  headache,  mental  fatigue  and  lassitude.  Conversely 
the  lack  of  sufficient  food  is  also  deleterious.  In  the  complete 
absence  of  food  life  can  rarely  be  sustained  over  ten  days.  An 
insufficient  diet  has  another  important  effect.  Individuals 
who  are  poorly  nourished  have  their  resistive  forces  lowered  to 
such  an  extent  that  they  fall  a  ready  prey  to  invasions  by  micro- 
organisms and  the  probabilities  of  a  fatal  termination  are  also 
much  greater.  This  is  illustrated  by  the  severe  epidemics  which 
have  so  frequently  been  associated  with  famine. 

Associated  with  the  question  of  an  insufficient  diet  is  the 
question  of  an  unbalanced  diet,  by  which  we  mean  one  in  which 
the  proper  proportion  of  protein,  carbohydrate  and  fat  are 
not  represented.  Economically  the  parallelism  of  poverty  and 
want  in  connection  with  these  is  sometimes  very  close,  though 
we  also  see  an  unbalanced  diet  resulting  from  a  perversion  of 
appetite  or  inability,  from  other  circumstances,  to  secure  the 
necessary  materials.  Thus  an  anemia  may  be  due  to  lack  of 
meat,  an  excess  of  carbohydrates  and  fats  may  produce  acne 
and  eczema  or  an  excessive  concentration  may  produce  con- 
stipation. In  addition  diseases  such  as  pellagra  and  beriberi 
appear  to  owe  their  origin  to  an  unbalanced  dietary.  We  shall 
discuss  these  briefly  later. 

Substances  consumed  as  food  may  exert  directly  a  toxic  or 

229 


23O  PRACTICAL   PREVENTIVE    MEDICINE 

injurious  action  on  the  body  in  various  ways.  Thus  ignorant 
people  may  undertake  to  use  naturally  poisonous  substances  as 
food  and  suffer  severely  as  a  consequence,  employing  for  ex- 
ample, toadstools,  certain  poisonous  fish  or  plants  containing 
toxic  alkaloids.  Through  accidents  in  preparation  or  for 
commercial  reasons,  extraneous  poisonous  substances  may  be 
present  in  toxic  amounts,  such  as  the  heavy  metals,  arsenic  or 
formaldehyde.  Or  the  food  stuffs,  while  normally  wholesome 
and  harmless,  may  through  some  natural  change  become 
toxic,  as  for  example  the  development  of  solanin  in  potatoes 
and  of  ergot  in  rye.  Some  will  consume  excessive  quantities 
of  alcoholic  beverages,  such  as  beer,  wines  or  whisky,  etc.  Or 
lastly  some  individuals  have  iodiosyncrasies  toward  certain 
foodstuffs.  The  manifestations  of  these  idiosyncrasies  very 
much  resemble  an  anaphylactic  reaction.  Among  the  food- 
stuffs for  which  these  reactions  have  been  noted,  are  straw- 
berries, certain  sea  foods,  eggs,  oatmeal  and  tomatoes. 

There  are  three  deficiency  diseases  whose  common  character 
warrants  their  receiving  especial  attention,  namely  scurvy,  beri- 
beri and  pellagra. 

SCURVY,  BERIBERI,  AND  PELLAGRA 

Definitions. — (a)  Scurvy  is  an  acute  or  chronic  disease  char- 
acterized by  debility,  mental  apathy  and  anemia,  with  spongi- 
ness  of  the  gums  and  ulcerations  of  the  mouth,  manifesting  a 
tendency  to  hemorrhages  into  the  subcutaneous  tissues  and 
from  the  mucous  surface. 

(b)  Beriberi  is  an  acute  or  chronic  disease  characterized  by 
changes  in  the  nervous  system,  and  particularly  by  a  multiple 
peripheral  neuritis,  with  an  especial  tendency  to  attack  the 
nerves  of  the  limbs,  the  pneumogastrics  and  the  phrenics,  with 
varying  degrees  of  cardiac  disturbances,,  oedema,  serous  effu- 
sions and  gastro-intestinal  derangements. 

(c)  Pellagra  is  an  acute  or  chronic  disease  characterized  by  a 
peculiar  erythema  and  dermatitis  on  those  parts  of  the  body 
exposed  to  the  sun's  rays,  by  salivation,  dyspepsia,  and  diarr- 
hoea, and  by  nervous  manifestations  which  may  terminate  in 
mental  disturbances  and  paralysis. 

Geographic  Distribution. — In  general  one  may  say  that  they 
are  world  wide,  though  varying  in  their  relative  prevalence,  as 
shown  in  the  following  table  which  indicates  their  greatest  in- 
cidence. 


DISEASES    DUE    TO    DIETARY   DEFICIENCIES 


23I 


Scurvy 


Has  prevailed  in  all  Euro- 
pean countries.  South- 
ern Asia,  Australia, 
South  Africa  and  Egypt 
and  the  United  States 


Beriberi 


Common  throughout  the 
Orient,  especially  in 
China,  Japan,  the  Phili- 
ippines,  India,  Africa 
and  South  America. 

Rare  in  the  United  States 


Pellagra 


Southern  Europe,  Italy, 
Spain,  Orient,  and  the 
Southern  United  States. 


Incidence. — They  may  occur  either  as  sporadic  cases  or  in  a 
wholesale  prevalence  simulating  epidemic  or  endemic  distribu- 
tion. Such  latter  instances  usually  occur  among  closely  cir- 
cumscribed groups  of  people,  such  as  soldiers  at  military  posts 
or  on  campaigns,  laborers  at  labor  camps,  exploring  parties, 
sailors  on  long  cruises,  inmates  of  jails,  penitentaries,  insane 
hospitals  and  other  similar  institutions. 

Past  Ideas  of  Etiology.— Widely  different  theories  of  their 
etiology  have  been  held  until  recently  and  these  we  shall 
briefly  review  before  passing  to  current  knowledge. 

(a)  Scurvy  has  been  variously  ascribed  to  :  (1)  a  deficiency 
of  potassium  in  the  blood;  (2)  a  decreased  alkalinity  of  the 
blood,  i.e.,  an  acidosis;  (3)  to  ptomaine  poisoning;  and  (4)  to  a 
specific  infection. 

(b)  Beriberi  has  been  ascribed  to;  (1)  poisoning  by  arsenic 
or  by  oxalates;  (2)  to  a  deficiency  of  nitrogen,  fat  or  phos- 
phorous; (3)  a  specific  infection;  or  (4)  as  an  unknown  intoxica- 
tion. 

(c)  Pellagra  has  been  variously  regarded  as:  (1)  an  intoxica- 
tion due  to  the  consumption  of  spoiled  corn;  (2)  as  a  specific 
infection,  either  transmitted  by  contact  or  by  the  agency  of  the 
small  black  flies  of  the  genus  Simulium;  or  as  an  intoxication 
due  to  colloidal  silica. 

Some  few  perhaps  still  adhere  to  some  of  the  foregoing  views, 
but  in  general  we  believe  that  the  majority  of  scientific  men 
regard  these  diseases  as  having  the  following  etiology. 

Present  Views  of  Etiology.— (a)  Scurvy  (Hoist  and  Frohch) 
is  found  to  be  due  to  a  deficiency  of  some  essential  constituent 
from  preserved  foods  but  which  is  present  in  all  kinds  of  fresh 
food,  both  animal  and  vegetable. 

(b)  Beriberi  (Fraser  and  Stanton,  Vedder,  et  al)  is  due  to  the 
removal  in  the  process  of  milling  and  polishing  rice  or  wheat, 
of  certain  substances  present  in  the  pericarp  of  the  grain,  which 
are  necessary  to  life  (Figs.  95,  96,  97,  98).     About  1  gm.  of 


232 


PRACTICAL    PREVENTIVE    MEDICINE 


this  substance  is  present  in  one  kilogram  of  rice  and  it  may  be 
extracted  from  rice  millings  by  alcohol.  By  its  employment  dry 
beriberi  and  experimental  polyneuritis  of  fowls  may  be  cured. 

(c)  Pellagra  (Goldberger  and  Wheeler)  is  due  to  a  diet  devoid 
of  meats  or  vegetable  fats.     It  has  been  produced  in  6  of  n 


Fig.  95. 


Pig.  96. 


Fig.  97.  Fig.  98. 

FiG.  95. — A  highly  milled  or  polished  rice  stained  by  Gram's  iodine  solution. 
The  starch,  being  completely  exposed,  stains  uniformly  a  dark  blue.  This  rice 
will  produce  beriberi. 

Fig.  96. — An  undermilled  rice  stained  in  the  same  way.  The  unstained  areas 
show  where  the  adherent  pericarp  has  protected  the  starch  from  the  action  of 
the  iodine.     This  rice  will  probably  not  produce  beriberi. 

Fig.  97. — A  sample  of  undermilled  rice  that  contains  still  more  pericarp.  The 
use  of  this  rice  will  surely  prevent  the  development  of  beriberi. 

Fig.  98. — The  unhusked  groid  or  "palay."  When  the  husks  are  removed 
by  hand  pounding,  a  rice  like  Fig.  97  or  Fig.  96  is  produced.  {From  Vedder, 
"Beriberi,"  Wm.  Wood  and  Co.,  Publishers .) 

convicts  by  a  five  months  diet  of  biscuits,  cornbread,  collards, 
grits,  rice,  fried  mush,  brown  gravy,  sweet  potatoes,  cabbage 
and  cane  syrup.  Some  are  inclined  to  dispute  the  correctness 
of  the  diagnosis  of  pellagra  among  the  subjects  in  this  experi- 
ment. 


DISEASES    DUE    TO    DIETARY   DEFICIENCIES  233 

Vitamins  or  Accessory  Food  Factors. — Based  upon  the  dis- 
covery of  the  therapeutic  value  of  rice  milling  extracts  in  the 
cure  of  beriberi,  these  diseases  have  been  ascribed  to  the  ab- 
sence of  minute  quantities  of  certain  substances  from  the  diet. 
Recent  researches  by  Funk,  McCallum  and  others  have  so  far 
resulted  in  the  recognition  of  two  of  these  substances  in  food- 
stuffs, one  of  which  is  soluble  in  water,  the  other  in  fats.  Their 
chemical  nature  is  unknown.  These  are  also  designated  fac- 
tors B  and  A  respectively.  The  beriberi  vitamin  or  antineuritic 
factor  is  identified  with  the  water  soluble  factor  B.  Both  of 
these  are  experimentally  found  to  be  essential  for  growth  and 
maintenance.  From  the  known  relationship  of  scurvy  to 
preserved  foods,  a  third  vitamin,  an  antiscorbutic  factor,  is 
assumed  to  exist  in  fresh  vegetable  food.  To  fat  soluble  A 
are  attributed  antirachitic  properties.  Thus  in  addition  to 
possessing  a  knowledge  of  the  protein,  carbohydrate  and  fat 
content  of  a  dietary,  it  is  also  necessary  to  consider  its  content 
of  vitamines  or  accessory  food  factors.  The  utilization  of  these 
substances  in  the  body  is  not  certainly  known,  but  Green  con- 
siders their  main  functions  concern  the  gross  metabolism  of 
food,  probably  principally  in  oxidative  catabolism. 

The  water  soluble  B  is  chiefly  secured  from  grain  (germ  and 
pericarp),  eggs,  yeast  and  legumes  (entire  seed).  The  fat 
soluble  A  is  chiefly  secured  in  cream,  butter,  cod  liver  oil, 
egg  yolk  and  green  legumes.  The  antiscorbutic  factor  is  chiefly 
found  in  cabbage,  turnips,  lettuce,  cresses,  tomatoes,  oranges 
and  citrus  fruits,  and  to  a  lesser  extent  in  potatoes  and  carrots. 
It  is  destroyed  in  any  dried  food.  In  general  the  vitamins  are 
destroyed  or  lost  by  cooking,  by  overheating  (milk),  by  laking 
out  in  boiling,  by  too  prolonged  desiccation  or  by  discarding 
the  outer  covering  of  grains. 

The  Individual  Prevention  and  Cure  of  these  Diseases. — 

(a)  Scurvy:  Among  these  groups  where  scurvy  has  appeared 
the  disease  has  disappeared  following  the  addition  of  either: 
(1)  juice  of  fresh  sweet  limes  or  lemons;  (2)  infusions  of  malt, 
(3)  sauerkraut,  (4)  milk  or  (5)  fresh  potatoes  to  the  dietary. 

(b)  Beriberi  too  has  disappearaed  or  has  not  developed  with 
diets  having  the  following  characteristics:  reduction  of  the 
amount  of  rice  or  a  substitution  of  unmilled  for  polished  rice, 
and  the  addition  of  legumes  and  other  vegetables. 

(c)  According  to  Goldberger  by  increasing  the  amount  of 
fresh  animal  food  and  legumes  in  the  diet  of  the  inmates  of 
three  institutions  where  pellagra  has  been  prevalent,  he  has 


234  PRACTICAL   PREVENTIVE    MEDICINE 

prevented  its  recurrance  during  a  period  of  one  year,  even  among 
those  individuals  who  were  pellagrins  during  previous  years. 

Public  Protection. — The  problem  of  dealing  with  these  dis- 
eases from  a  public  standpoint  is  more  difficult  of  attack  than  is 
the  administrative  control  of  communicable  diseases,  and  prob- 
ably is  more  dependent  upon  popular  education. 

(a)  Beriberi  can  probably  be  publically  controlled  by  placing 
a  prohibitive  tax  on  the  sale  of  polished  rice. 

(b)  Pellagra  on  the  other  hand,  is  more  difficult.  An  in- 
creased consumption  of  milk,  eggs,  legumes  and  fresh  vege- 
tables, together  with  meats  is  necessary.  To  a  large  extent 
this  requires  an  improvement  in  the  economic  condition  of  the 
wage  earners  to  enable  them  to  increase  their  living  standards. 
Some  of  this  can  be  accomplished  by  domestic  gardening  and 
chicken  raising. 

ALCOHOLISM 

Thanks  to  national  prohibition  this  disease  will  soon  be  a 
matter  of  historical  interest  in  the  United  States.  The  con- 
sumption of  alcoholic  beverages  for  their  stimulating  effect  is 
a  world  wide  habit  of  long  antiquity.  The  evils  it  produces  are 
both  directly  and  indirectly  due  to  its  agency,  and  are  both 
hygienic  and  economic.  The  latter  is  outside  our  province 
to  discuss.  As  a  contributing  factor  it  is  of  wide  spread  impor- 
tance in  commercial  prostitution  and  hence  is  an  important 
factor  in  the  dissemination  of  venereal  diseases.  The  elimina- 
tion of  alcohol  will  go  far  to  reduce  commercial  prostitution  and 
hence  reduce  the  extent  to  which  venereal  diseases  are  trans- 
mitted. Directly  it  is  chiefly  of  importance  as  a  cause  of  mental 
disturbances  or  psychoses.  It  is  the  direct  cause  of  Korsakoff's 
psychosis,  alcoholic  hallucinations,  delerium  tremens  and 
alcoholic  deterioration.  It  is  a  contributory  cause  to  others. 
This  group  of  psychoses  are  responsible  for  about  twelve  per 
cent,  of  all  first  admissions  to  hospitals  for  the  insane,  and  in 
general  are  more  common  in  males  than  females,  and  in  those 
from  cities  as  compared  with  rural  inhabitants.  It  is  uncer- 
tain whether  alcoholism  is  a  factor  in  the  hereditary  trans- 
mission of  mental  deficiency. 

REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene,  3rd.  Ed.,  pp.  516-659. 
Winton:  Food  Analysis. 

The   Chemical   Composition  of  American  Food   Materials.     Bull.   28,  Office 
of  Exp't  Stations,  U.  S.  Dept.  Agriculture. 


DISEASES    DUE    TO   DIETARY   DEFICIENCIES  235 

Some  Forms  of  Food  Adulteration  and  Simple  Methods  for  their  Detection, 

Bull.  100,  Bur.  Chemistry,  U.  S.  Dept.  Agriculture. 
Care  of  Food  in  the  Home,  Farmer's  Bull.  375. 
The  Sanitary  Construction  and  Equipment  of  Abattoir's  and  Packing  Houses. 

Circ.  173,  Bur.  Animal  Industry,  Dept.  Agriculture. 
Vedder:  Beriberi. 
Marie:  Pellagra. 
The   Treatment  and  Prevention  of   Pellagra.     Reprint  228,   Public  Health 

Reports.  ,         „      .       , 

Experimental  Pellagra  in  the  Human  Subject  Brought  About  by  a  Retncted 

Diet.     Reprint  311,  Public  Health  Reports. 
Pellagra:  A    Report    on    its    Epidemiology.     Reprint    120,    Public    Health 

Reports.  .  . 

Pellagra:  The  Value  of   the   Dietary  Treatment   of  the   Disease.      Reprint 

353,  Public  Health  Reprints.  _ 

The    Prevalence    and    Geographic    Distribution   of  Pellagra   in    the   United 

States.     Reprint  106,  Public  Health  Reports. 
Overton  and  Denno  "The  Health  Officer"  Chapter  XXXIII. 


SECTION  III 


OCCUPATIONAL  DISEASES 


CHAPTER  XXVI 


HAZARDS  OF  OCCUPATION 

In  the  pursuit  of  a  livelihood  wage  earners  are  exposed  to 
varying  risks  and  hazards,  some  of  which  are  peculiar  to  their 
occupation  while  others  arise  as  a  result  of  their  own  or  some 
one  else's  carelessness.  We  shall  consider  briefly  the  more 
important  of  these. 

i.  From  the  standpoint  of  the  number  and  gravity  of  the 
hazards  encountered  the  principal  occupations  of  mankind  may 
be  grouped  as  follows: 


Occupational  class 
Manufacturing  and  Mechanical 
Industries 


C. 
D. 


Transportation     (railroad    men 

and  sailors). 

Construction  Work. 
Mining   and   the   extraction   of 

minerals. 


Character  cf  hazards 

(a)  Unsanitary  home  environment. 

(b)  Employment     in     unhygienic     sur- 

roundings. 

(c)  Inadequate  lighting  and  ventilation. 

(d)  Inadequate  toilet  facilities. 

(e)  Infection. 

(/)  Dust,  fumes  and  poisons. 

(g  Unguarded,  carelessy  operated,  or 

defective  machinery, 
(/z)  Fire  hazards,  increased  air  pressure. 


(a) 
(a) 


Same  as  above. 
Same  as  above. 


a)  Unsanitary  home  environment. 

(b)  Premature  explosions. 

(c)  Fire  damp,  fires  and  dust. 

d)  Unguarded  and  defective  machinery. 
(e)  Fall  of  roof. 
(/)  Poisons. 

(g)    Underground  work,  excessive  heat 
or  moisture. 


236 


HAZARDS    OF    OCCUPATION  237 

E.  Agriculture,  forestry  and  animal 

husbandry.  (a)  Unsanitary  home  environment. 

(b)  Accidents     from     machinery     and 

timber. 

(c)  Infection  from  livestock. 

(a)    Defective  hygienic  conditions. 


F.    Mercantile  and  Clerical  Pursuits. 


(b)  Inactivity,  fatigue. 


G.  Individual  service,  public,  pro- 
fessional and  domestic  (a)  Xo  distinctive  hazards. 

From  the  foregoing  it  can  be  seen  that  different  occupations 
vary  in  the  number  and  variety  of  hazards  encountered,  some 
are  common  to  many,  others  are  peculiar  tc  a  group.  We  shall 
next  consider  the  principal  individual  hazards,  their  danger  and 
the  means  of  their  amelioration. 

2.  Unsanitary  Home  Environment. — The  development  of 
manufacturing  industries,  mines,  or  construction  enterprises  is 
frequently  in  situations  inconveniently  distant  from  previously 
existing  cities  or  towns,  or  the  number  of  workmen  required  for 
the  enterprise  is  far  greater  than  the  number  of  vacant  homes 
available.  For  this  reason  large  companies  have  frequently 
built  residence  towns  or  additions  to  existing  towns  to  accom- 
modate their  employees.  Many  of  these  towns  and  the  dwell- 
ings which  comprise  them  have  been  constructed  with  very  little 
thought  to  the  welfare  of  those  who  must  occupy  them.  The 
houses  may  be  illy  lighted  or  ventilated,  water  supply  and 
excreta  disposal  are  inadequate,  mosquito  breeding  is  permitted 
and  gross  overcrowding  may  prevail.  On  the  other  hand  many 
enlightened  corporations  have  constructed  towns  of  model 
dwellings. 

Some  rural  or  agricultural  homes  are  fully  as  bad  or  even 
worse    than    those    in    the    slum    districts    of    large    cities. 

3.  Inadequate  Ventilation. — Many  industrial  processes  give 
rise  to  dust  and  fumes,  some  of  which  are  poisonous.  In  the 
vicinity  of  furnaces  and  open  flames  the  oxygen  content  of  the 
air  is  frequently  much  below  normal,  and  the  air  may  also  be 
very  smoky.  Under  these  conditions  the  air  is  certain  to  be 
very  hot,  or  under  other  conditions  may  be  excessively  humid 
as  well.  For  this  condition  exhaust  ventilation  is  the  best 
remedy,  with  the  exhaust  intakes  placed  close  to  the  situations 
where  dust  or  fumes  are  produced. 

4.  Inadequate  Lighting. — Natural  illumination  is  frequently 
insufficient.     Artificial  illumination  is  likewise  frequently  in- 


238  PRACTICAL   PREVENTIVE    MEDICINE 

sufficient  or  improperly  employed,  so  that  the  work  is  poorly 
illuminated  or  the  light  shines  in  the  workmen's  eyes.  Where 
a  blinding  illumination  must  be  tolerated  goggles  are  necessary. 

5.  Excessive  Heat. — The  bad  effects  of  excessive  heat  may  be 
counterbalanced  by  the  use  of  goggles,  body  shields,  air  blasts, 
fans  and  water  sprays.  The  workmen  exposed  to  excessive  heat 
should  have  a  short  work  day,  and  shower  baths  should  be  avail- 
able for  their  use  when  leaving  work. 

6.  Fatigue  and  Inactivity. — Fatigue  is  the  chief  cause  of 
accidents  from  carelessness  and  furthermore  decreases  produc- 
tion. It  arises  from  laborious  work,  long  hours,  piece  work, 
speeding  up  practices,  monotony,  constant  standing  or  a  con- 
stant strained  position,  the  use  of  chairs  or  stools  without 
backs,  faulty  postures,  jarring  operations,  the  pressing  or  hold- 
ing of  objects  against  the  body,  eyestrain,  loud  noises,  irregular 
hours  of  sleep  and  the  absence  of  work  variation  or  periods  of 
relaxation.  Similarly  the  inactivity  of  the  sedentary  worker 
induces  fatigue.  It  is  one  of  the  most  important  problems  in 
industrial  hygiene. 

7.  Extremes  of  Humidity. — Sedentary  work  should  not  be 
done  in  a  humid  atmosphere.  If  the  air  be  excessively  dry, 
provision  should  be  made  for  its  humidification. 

8.  Dust  affects  the  lungs,  the  skin,  the  eyes  and  the  external 
auditory  canal.  Protection  from  it  may  be  secured  by  the  use 
of  goggles,  respirators,  wet  processes,  exhaust  ventilation  and 
the  avoidance  of  dry  sweeping.  Of  the  different  dusts  en- 
countered in  industries,  soil  dust  is  the  least  harmful,  then  in 
order  of  increasing  danger  come  flour  and  starch,  soapstone  and 
talc,  wood  dust,  bran  dust,  coal  dust,  clay  dust,  shell  dust,  ore 
dust,  mineral  dust  and  stone  dust.  These  dusts  may  be  either 
poisonous  or  irritating.  The  latter  have  an  important  rela- 
tionship to  industrial  tuberculosis.  The  problem  of  dust  will 
be  considered  later  in  more  detail. 

9.  Poisons  are  encountered  in  industry  as  either  fumes,  gases, 
solutions,  pastes  or  solids.  The  list  includes  lead,  benzine, 
benzol,  turpentine,  brass  or  zinc  fumes,  acids,  alkalies,  wood 
alcohol,  anilin  oil,  carbon  bisulphid,  antimony,  illuminating 
and  fuel  gas,  hydrogen  sulphide,  arsenic,  phosphorous,  mercury 
and  cyanide.  Industrial  poisonings  usually  occur  because  the 
amount  of  risk  is  not  appreciated  either  by  the  employees  or  the 
employer.  In  combating  their  danger  it  is  frequently  necessary 
to  overcome  the  following  handicaps:  (1)  an  employer's  policy 
of  keeping  the  employees  in  ignorance  of  the  poisons  used; 


HAZARDS    OF    OCCUPATION 


239 


(2)  misbranding  of  poisonous  substances;  (3)  lack  of  instruc- 
tions or,  (4)  disregard  of  instructions;  (5)  absence  of  mechanical 
health  appliances,  such  as  adequate  ventilation;  (6)  permitting 
employees  to  eat  while  at  work  or  in  the  work  rooms;  (7)  lack 
of  personal  cleanliness  among  employees;  (8)  lack  of  sufficient 
washing  facilities;  (9)  absence  of  gloves  and  respirators;  and 
(10)  no  change  of  clothing  on  leaving  work.  Each  poison 
presents  a  different  problem.  These  also  will  later  receive 
more  detailed  consideration. 


Fig.  99. — Rotary  shears  before  and  after  protecting.  Notice — "Stop  this 
machine  when  oiling,  wiping  or  repairing."  Tennessee  Coal,  Iron  and  Railroad 
Company.      (Bull.  4,  U.  S.  Steel  Corp.) 

10.  Infections. — Infections  may  be  contracted  either  from 
other  workmen  by  the  agencies  of  contact,  or  from  the  mate- 
rial handled.  Wounds  received  while  at  work  and  improperly 
cared  for  may  become  seriously  infected.  Contact  transmission 
is  favored  by  overcrowding,  by  the  use  of  common  towels  and 
drinking  cups,  absence  of  cuspidors  and  consequent  spitting 
on  the  floors,  by  sweeping  during  working  hours,  and  by  mouth- 
ing objects  handled  by  another.  Agriculturists  may  become 
infected  from  sick  livestock,  while  workers  in  hair  and  wool 
may  become  infected  with  anthrax  from  this  material.  A  cer- 
tain degree  of  protection  is  afforded  by  first  aid  training,  but 


240 


PRACTICAL    PREVENTIVE    MEDICINE 


still  better  in  a  manufacturing  plant  is  a  surgical  emergency 
room  with  a  trained  nurse  in  charge,  and  a' supervising  surgeon. 
ii.  Unguarded  or  Defective  Machinery. — This  is  one  of  the 
most  potent  sources  of  danger.  The  following  moving  parts 
of  machinery  should  be  protected  by  suitable  guards  so  that 
hair,  clothing,  or  the  ringers  may  not  be  caught  or  the  person 
crushed  or  mangled,  viz.:  gears,  rolls  (Fig.  99),  belting,  rope 
or  chain  drives,  all  horizontal  belts  or  shafting  less  than  seven 
feet  from  the  floor,  beltshifts  or  loose  pulleys,  clutches,  shaft 
guards  and  set  screws.  Fly  wheels  and  emery  wheels  should 
also  be  guarded,  and  the  latter  should  be  suitably  connected 


-Mil 

r' 

a-              -**      n^— • 

• 
l"%  V*  ■'■-■  *v 

Pig.  100. — Concentrating  plant  Oliver  Iron  Mining  Co.  32,000  feet  of  pipe 
for  hand  and  guard  rails  were  used  in  connection  with  platforms  at  this  plant, 
giving  safe  access  to  all  machinery.  Guarded  platforms.  {Bull.  4,  U.  S. 
Steel  Corp.) 

to  an  exhaust  vent.  Additional  points  for  safety  in  factories 
are  the  following:  (i)  Glass  panels  on  swinging  doors  in  passage- 
ways, (2)  ladders  should  have  sharp  points  on  their  feet,  (3) 
elevated  platforms  around  machinery  should  be  railed  (Fig.  100), 
(4)  saws  of  different  types  and  planes  should  have  suitable 
guards.  Convenient  provision  should  be  made  for  the  rapid 
shutting  off  of  power  in  the  event  someone  is  caught.  Similarly 
power  of  any  sort  should  not  be  turned  on,  or  machinery  set  in 
motion,  unless  it  is  known  that  no  one  is  in  a  position  to  be 
injured. 

12.  Transportation  Hazards. — Employees  suffer  from  these 
more  than  passengers,  while  trespassers  suffer  the  most.     Acci- 


HAZARDS    OF    OCCUPATION 


241 


dents  upon  the  railroad  are  mainly  due  to  the  following:  Care- 
lessness,, lack  of  discipline,  overwork,  and  the  lack  of  safety 
devices.  Passengers  mainly  suffer  from  derailment  and  collis- 
ions while  employees  suffer  from  accidents  arising  in  coupling 
and  uncoupling  cars,  and  by  falling  from  cars  or  engines. 

13.  Mining  and  quarrying  have  types  of  peculiar  hazards  such 
as  fall  of  roof  and  explosions.  The  former  can  largely  be  elimi- 
nated by  proper  timbering.  Explosions  are  due  to  different 
causes.  Float  dust  containing  10  per  cent,  or  more  of  volatile 
matter  is  very  explosive  when  brought  in  contact  with  a  naked 
flame.  It  should  either  be  wet  down  or  covered  with  stone  dust. 
Fire  damp  (CH4  and  O)  explodes  either  from  a  naked  flame  or 


Fig.    ioi. — Rescuing    fellow-workman.      Miners    equipped    with    breathing    ap- 
paratus.     (Bull.  4,    U.  S.  Steel  Corp.) 

a  shot.  Danger  from  CO  in  old  workings  can  be  readily  de- 
tected by  the  use  of  canary  birds  (Fig.  102).  Many  explosions 
of  dust  or  fire  damp  are  due  to  the  flame  produced  by  explosives. 
Accordingly  the  so-called  permissible  explosive  only  should 
be  employed.  These  do  not  produce  a  big  flame.  Miners 
should  not  tamp  down  charges  of  explosives  with  metal  rods, 
due  to  the  danger  of  premature  explosions.  Charges  should 
be  fired  from  a  central  switch  after  all  men  are  checked  out  from 
the  mine.  Fire  danger  can  largely  be  eliminated  by  the  use  of 
safety  lamps  and  the  protection  of  the  shaft  (Fig.  101).  Addi- 
tional dangers  encountered  are  from  collisions  between  cars 
and  lack  of  clearance  between  the  cars  and  the  wall,  and  also  of 
electrocution  from  low  overhead  trolley  wires. 

16 


242 


PRACTICAL   PREVENTIVE   MEDICINE 


14.  Air  Pressure. — Increased  air  pressure  is  only  encountered 
by  the  "mud  hogs"  in  caissons,  in  whom  rapid  decompression 
may  produce  the  condition  known  as  the  "bends."  This  can 
be  avoided  by  their  gradual  decompression  in  the  air  locks. 
(Fig.  103). 

15.  Fire  hazards  are  numerous  and  varied.  They  are 
affected  by  the  inflammability  of  the  building  or  of  raw  mate- 
rials stored  therein.  Fire  escapes  should  be  adequate  for  the 
number  of  individuals  in  the  building.  In  this  connection  we 
may  call  attention  to  the  fact  that  the  stair  escapes  permit  more 
rapid  escape  from  a  building  than  the  ladder  type.  They 
should  preferably  be  built  along  a  blank  wall  and  connected  to 


Ml  "  ~ 


Pig.  102. — The  canary  is  to  the  mine  rescue  crew  what  a  thermometer  is  to 
the  physician.  The  bird  is  more  susceptible  to  gas  than  human  beings  and 
when  it  topples  from  the  perch  in  its  little  cage  the  rescue  men  know  they  have 
gas  to  reckon  with.      (G.  H.  Taylor:  The  Survey.) 

windows  by  platforms.  Regular  fire  drills  at  unexpected 
moments  will  do  much  to  permit  an  orderly  exit  when  danger 
threatens.  Lack  of  judgment  in  the  location  of  the  stair  wells 
and  elevator  shafts  frequently  does  much  to  spread  a  fire  and 
prevent  the  escape  of  the  inmates.  If  exit  doors  open  outward 
their  jamming  by  a  panic  stricken  crowd  will  be  largely  pre- 
vented. Fire  risk  from  inflammable  or  explosive  gases  will 
be  much  lowered  by  adequate  ventilation.  Automatic  sprink- 
lers will  usually  keep  blazes  from  spreading,  and  extinguish 
them  in  their  incipiency. 

16.  Electrical  Accidents. — Electric  installations  offer  many 
opportunities   for   accidents   of   a  serious   character.     Danger 


HAZARDS    OF    OCCUPATION 


243 


signs  should  be  freely  employed  and  dangerous  parts  of  equip- 
ment should  be  painted  red.     Only  experienced  and  competent 


Fig  103. — Air-lock  on  top  of  caisson.  In  sinking  foundations  for  sky  scrap- 
ing buildings  men  go  down  beneath  the  water  level  and  work  in  compressed-air 
chambers  or  caissons.  The  air  pressure  is  frequently  more  than  three  times  the 
normal  fifteen  pounds  per  square  inch.  Workers,  if  released  gradually  during 
decompression  in  the  air-lock  avoid  the  "bends"  or  compressed-air  illness. 
(Industrial  Dis.  Am.  Labor  Leg.  Rev.,  1912.) 


men  should  be  allowed  in  rooms  where  dangerous  apparatus  or 
wires  are  installed,  and  no  man  should  be  left  alone  with  a 
high  tension  current.     Floors  that  are  in  dangerous  proximity 


244  PRACTICAL   PREVENTIVE   MEDICINE 

to  wires  at  high  tension  should  be  covered  with  insulating 
mats.  No  repairs  of  mains  or  wires,  or  examinations  or  altera- 
tions should  be  permitted  while  they  are  under  a  high  tension 
current.  Switches  should  be  provided  with  tell  tale  lamps,  and 
when  a  switch  is  thrown  open  it  should  be  tagged,  and  the 
switch  kept  open  until  the  completion  of  the  necessary  work  has 
been  reported.  Workmen  should  take  the  same  precautions 
with  dead  apparatus  that  they  do  with  live  apparatus.  Rubber 
gloves  should  be  worn  and  the  sleeves  kept  down.  When 
working  on  the  primary  side  of  transformers,  switchboards 
etc.,  only  one  hand  should  be  used.  Plenty  of  free  room  should 
be  maintained  about  the  switch  boards  and  their  backs  should 
be  enclosed.  All  motors,  generators,  transformers,  etc.,  should 
be  guarded  and  also  provided  with  insulated  platforms.  Termi- 
nals, brushes  and  connections  should  be  so  situated  that  they 
will  not  be  accidentally  touched. 

17.  The  most  important  factors  in  the  production  of  indus- 
trial accidents  are  the  following: 

(a)  Carelessness. 

(b)  Poor  light. 

(c)  Unsuitable  clothing. 

(d)  Cluttered  up  factories. 

(e)  Lack  of  safeguards. 
(/)  Fatigue,  and 

I)  Overcrowding  of  the  workmen  in  the  shop. 


CHAPTER  XXVII 


OCCUPATIONAL    INTOXICATIONS    AND    DISEASES 

Little  definite  data  can  be  presented  concerning  the  preva- 
lence of  occupational  diseases,  since  little  attention  has  been 
paid  them  until  recent  years,  and  but  four  states  require  their 
reporting.  Their  frequency  as  well  will  be  proportional  to 
the  prevailing  type  of  economic  development.  The  experience 
in  Ohio  will  give  us  perhaps  our  best  guide  to  their  prevalence. 
Thus  recently  during  a  period  of  seventeen  months,  there  were 
reported  a  total  of  1204  cases  of  occupational  diseases.  The 
following  were  the  most  numerous: 

Benzene  and  benzol  poisoning 33  cases 

Brass  poisoning 124  cases 

Lead  poisoning 544  cases 

Pneumonokoniosis 15  cases 

1.  Thus  we  see  lead  poisoning  is  by  far  the  most  important. 
Its  importance  is  emphasized  if  we  briefly  survey  the  many 
occupations  in  which  lead  is  handled  and  among  whose  workers 
lead  poisoning  may  arise.  This  is  presented  in  the  following 
table,  which  represents  the  cases  reported  above. 

TABLE  IX. — Industiues  in  which  Lead  Poisoning  May  Occur 


Industry 

Trade  process 

No.  of  cases 

Painting  and  bronzing 

4 

Automobiles  and  parts 

Babbiting  metals  and  solder 

Bicycles  and  sewing  machines. . . . 

Brass  and  bronze  products 

Carriages,  wagons  and  parts 

Cars  and  repairs  (R.  R.) 

Carpentering  on  primed  work, 

painting  and  sanding  (Fig.  106) 

Melting 

79 

1 

Painting  and  varnishing 

Founding  and  soldering 

Painting  and  sanding 

Painting,  soldering,  varnishing.  . 
Painting  and  varnishing 

2 

3 

42 
3 

Cars  and  repairs  (not  R.  R.) 

6 
2 

Chemicals 

Lead  burning,  ore  crushing 

6 

'45 


246 


PRACTICAL   PREVENTIVE    MEDICINE 
TABLE  IX. — {Continued) 


Industry 


Trade  process 


No.  of  cases 


Coffins,  vaults,  etc. 


Copper,  tin.  etc 

Cutlery  and  tools. . . 
Electrical  apparatus. 


Enameling  and  japanning 

Files 

Flags,  regalia,  etc 

Foundry     and     machine       shop 
products 


Furniture  and  cabinets. 
Glass  manufacture 


Scientific  instruments 

Tin  and  sheet  rolling  mills 

Lead  bar,  pipes,  sheets,  etc 

Lead  oxides  and  carbonates 

Oil  refining 

Paint  and  varnish  manufacture.  .  . 

Painting    and    varnishing     (non 

mfg.) 

Porcelain  enameled  iron  ware .  .  . 

Pottery 

Printing  and  publishing 


Rubber  goods 

Safes  and  vaults 

Scales  and  balances 

Ship  building. 

Signs  and  adv.  novelties. . 
Smelting  and  refining.  .  .  . 
Stereo  and  electroplating. 

Stoves  and  furnaces 

Wire  (works  and  mills) .  .  . 
Miscellaneous 


Brass  and  lead  founding,  paint- 
ing, varnishing,  buffing  and 
soldering 

Machine  shopping,  soldering. . . . 

Tempering 

Lead  burning,  storage  batteries, 
soldering 

Enameling 

File  cutting  and  tempering 

Painting 


Die  casting,  founding, painting, 
soldering 

Painting  and  varnishing 

Lead  putty  working,  mixing  in- 
gredients  

Metal  grinding,  soldering 

Tinning 

Various  processes 

Various  processes 

Handling  lead  pipes 

Grinding,    mixing,    filing   con- 
tainers, soldering,  labelling. .  . 


House  painting 

Enameling 

Glazing  processes,  etc 

Linotyping  (Fig.  104),  type  set- 
ting, etc 

Compounding,  mixing,  etc 

Painting  and  sanding 

Painting 

Soldering 

Painting 

Metal  refining 

Casting 

Soldering , 

Galvanizing,  painting,  etc 


13 
3 

7 

107 
3 
3 


36 


25 


4 
61 

5 

43 

6 

7 
1 

1 

4 

1 

3 
3 


From  the  foregoing  it  can  be  seen  that  the  industries  in  which 
lead  products  are  employed  are  varied,  and  that  men  engaged 


OCCUPATIONAL   INTOXICATIONS   AND   DISEASES 


247 


in  considerably  different  occupations  may  suffer  from  lead 
poisoning.  Painters  and  those  who  sandpaper  (Figs.  105,  106) 
painted  work,  workers  in  storage  batteries,  workers  in  rubber 
manufacture,  printers  (Fig.  104)  and  workers  in  lead  products 
are  the  heaviest  sufferers.  The  possibility  of  lead  poisoning 
must  always  be  borne  in  mind  in  the  clinical  examination  of  an 
industrial  patient. 

2.  Channels  by  which  Lead  Gains  Entrance  into  the  Body. — 
In  most  manufacturing  processes  lead  as  a  poison  is  encountered 


Fig.  104. — Showing  installation  of  exhaust  system  for  linotype  machines. 
Each  machine  has  a  molten  pot  of  type  metal  (lead  alloy)  from  which  lead  fumes 
arise.      (Bull.  209,  Bur.  Labor  Stat.) 


in  the  form  of  dust,  as  well  as  in  lead  smelting  and  the  manufac- 
tures of  lead  carbonate.  Absorption  by  the  lungs  appears  to 
be  slight,  the  greater  amount  of  dust  gaining  entrance  by  the 
alimentary  canal.  Most  dust  is  caught  in  the  nasopharynx 
and  swallowed  with  the  mucous  secretions.  The  dust  on  enter- 
ing the  stomach  reacts  with  the  hydrochloric  acid  and  soluble 
chlorids  are  formed  which  are  absorbed.  When  it  reaches  the 
blood  it  is  believed  to  form  a  rather  insoluble  albuminate.  If 
food  is  eaten  at  the  same  time  less  lead  will  be  converted  to 


248 


PRACTICAL    PREVENTIVE    MEDICINE 


Fig.  105. — Dry  sandpapering.  Dry  sanding  of  paint  is  a  frequent  cause  of 
lead  poisoning.  The  operation  fills  the  air  with  tiny  particles  of  lead  dust. 
{Industrial  Dis.,  Am.  Labor  Legislation  Review,  1912.) 


Fig.  106. — Wet  sanding  with  pumice  stone.  Dust  is  avoided  when  sanding 
is  done  with  wet  pumice  stone.  (Industrial  Dis.,  Am.  Labor  Legislation  Review, 
1912.) 


OCCUPATIONAL   INTOXICATIONS    AND   DISEASES  249 

the  chlorid.  Lead  which  is  not  changed  to  the  chlorid  passes 
out  into  the  feces  as  the  sulphid.  Lead  carbonate  is  more  solu- 
ble in  the  gastric  juices  than  the  sulphate. 

In  intoxication  from  lead  fumes  absorption  is  by  the  way  of 
the  lungs.  It  is  a  less  common  route  than  the  alimentary, 
the  principle  occupations  affected  by  this  route  being  lead 
smelters  and  linotype  operators.     (Fig.  104). 

3.  Symptomatology  of  Lead  Poisoning. — Females  and  young 
persons  are  predisposed  to  lead  poisoning.  The  onset  is  very 
variable,  usually  manifesting  itself  in  two  to  four  weeks,  rarely 
longer.  The  onset  is  more  certain  and  the  symptoms  more 
severe  when  small  doses  are  absorbed  over  long  periods.  A 
gradually  developing  pallor  (anemia)  with  basophilic  stippling 
of  the  red  cells,  a  blue  line  on  the  gums  close  to  the  dental 
margin,  colic  and  constipation  with  headache  are  usually 
observed.  The  patient  may  have  convulsions,  disturbances  of 
vision  or  paralysis.     Pregnant  women  always  miscarry. 

4.  Remedies. — Efficient  exhaust  ventilation  is  essential  for 
the  removal  of  both  dust  and  fumes.  The  amount  of  dust 
produced  can  frequently  be  reduced  by  slight  alterations  in 
methods.  Provision  should  be  made  so  that  a  little  food  can 
be  kept  in  the  stomach  during  working  hours.  Workmen 
should  be  instructed  to  expectorate  saliva  instead  of  swallowing 
it.  Adequate  washing  facilities  will  assist  in  removing  dust,  as 
will  also  the  requirement  that  the  clothing  be  changed  upon 
leaving  work.  In  the  painting  trades  much  will  be  accom- 
plished by  the  substitution  where  possible  of  zinc  paints  for 
lead  paints. 

5.  Arsenic. — Arsenic  is  chiefly  encountered  as  a  dust. 
Workers  in  the  manufacture  of  Scheele's  Green  (  a  pigment), 
wall  paper,  glazed  colored  paper,  artificial  flowers,  the  packing 
of  white  arsenic  and  at  works  where  the  ore  is  reduced,  are 
affected.  It  acts  as  an  irritant  to  the  skin  and  mucous  surfaces. 
(Fig.  107,  108). 

6.  Mercury. — A  variety  of  different  mercury  salts  and  the 
metal  itself  may  produce  intoxication  from  the  action  of  either 
dust  or  fumes.  Thus  we  find  that  cinnibar  roasters,  workers 
in  the  extraction  of  gold  and  silver,  the  users  of  mercury  air 
pumps,  barometer  or  thermometer  manufactures,  water  gilders 
and  felt  hat  and  fur  dressers  may  become  intoxicated.  Its 
prevention  chiefly  requires  improvement  in  ventilating  facilities. 

7.  Benzin  and  Benzol. — These  are  chiefly  used  as  solvents 
for  quick  drying  paints  and  varnishes,  for  cements  and  blacking. 


25° 


PRACTICAL   PREVENTIVE    MEDICINE 


Fig.   107. — Arsenic  poisoning.      Putting  Paris  green  into  a  bolter.     An  old  and 
dangerous  method.      (Industrial  Dis,  Am.  Labor  Leg.  Rev.,  1912) 


Fig.   108. — Arsenic    poisoning.     A    comparatively    dustless    bolter.     Respira- 
tors worn  as  an  additional  protection.     (Industrial  Dis.,  Am.  Labor  Leg.  Rev.,  1912.) 


OCCUPATIONAL   INTOXICATIONS    AND    DISEASES 


251 


Fig.  109. — Room  at  boot  and  shoe  factory.  Women  and  girls  are  exposed 
to  the  fumes  of  naphtha  from  open  bowls  of  cement.  (Bull.  127,  Bur.  Labor 
Stat.) 


Fig.  1 10. — Casting  yellow  brass.  When  the  molten  metal  is  poured  into  the 
molds,  fumes  of  zinc  arise  and  are  precipitated  by  the  cool  air  of  the  room  into 
fine  gray  powdered  flakes.  In  the  room  shown  these  are  unavoidably  inhaled 
by  the  workmen,  who  are  thus  exposed  to  the  disease  known  as  brass  founders' 
ague.      (Bull.  127,   Bur.  Labor  Stat.) 


252  PRACTICAL    PREVENTIVE    MEDICINE 

Those  exposed  are  chiefly  cementers  in  the  rubber  and  boot 
and  shoe  industries,  as  well  as  dry  cleaners  and  painters.  They 
produce  faintness  and  stupor.  Adequate  ventilation  is  re- 
quired for  prevention.  (Fig.  109). 

8.  Zinc  Poisoning  f Brass  Founders  Ague). — Brass  is  an 
alloy  of  zinc  and  copper  in  varying  proportions.  When  brass 
is  melted  a  considerable  volume  of  zinc  oxide  is  given  off  as 
fumes.  (See  Fig.  no).  Thus  brass  moulders  are  chiefly 
exposed,  though  brass  polishers  suffer  to  a  lesser  extent.  The 
attacks  are  acute  and  come  on  several  hours  after  exposure. 
The  workmen  suffer  from  rigors  followed  by  a  fever,  the  whole 
lasting  several  hours.  Chronically  it  may  also  produce 
asthmatic  and  bronchial  symptoms.  Efficient  exhaust  ventila- 
tion is  required  as  a  remedy. 

9.  Pneumonokoniosis. — Pneumonokoniosis  is  a  chronic  inter- 
stitial pneumonia  accompanied  by  a  deposit  of  pigment  and 
usually  due  to  dust  encountered  under  conditions  of  employ- 
ment. The  physical  character  of  the  dust  is  an  important 
factor  in  the  development  of  the  condition.  It  affects  workers 
in  coal  and  stone,  clay,  iron,  wool,  flour,  tobacco,  iron  oxide, 
ultramarine  blue,  hair,  cotton,  shell,  leather  and  wool. 

Dust  enters  the  lungs  both  by  inhalation  and  the  alimentary 
tract.  Inhalation  is  probably  the  most  important  route. 
The  inhaled  particles  pass  to  the  alveoli  despite  the  obstacles 
presented  by  the  ciliated  epithelium  and  the  minute  subdivi- 
sions of  the  bronchioles.  They  are  ingested  by  the  phagocytic 
epithelial  cells  which  carry  them  to  the  connective  tissue  frame 
work  of  the  lungs  or  to  the  lymphatics,  and  are  later  deposited 
in  the  bronchial  glands.  Those  which  settle  in  the  mouth  are 
enmeshed  in  the  pharyngeal  mucus  and  swallowed.  Phagocytes 
carry  them  through  the  intestinal  walls  to  the  lymphatics, 
by  which  route  they  are  carried  to  the  lungs. 

An  important  related  point  is  the  fact  that  about  seventy 
per  cent,  of  these  persons  develop  pulmonary  tuberculosis, 
doubtless  due  to  the  irritation  developed.  Tuberculosis 
mortality  is  about  four  times  as  great  among  workers  in  dusty 
trades  as  in  the  population  as  a  whole.  The  harder  and  sharper 
the  dust  the  more  likely  is  the  condition  to  develop.  It  is 
relatively  rare  among  workers  in  organic  dust,  in  whom  the 
dust  usually  sets  up  a  chronic  catarrhal  condition  which  only 
rarely  leads  to  structural  changes.  Various  terms  are  used  to 
designate  this  condition  when  produced  by  different  dusts. 
Thus    in: 


OCCUPATIONAL    INTOXICATIONS    AND    DISEASES  253 

(a)  Coal  miners   (especially  in  hard   coal)   it  is  known  as 
Anthracosis. 

(b)  Quartz  miners  (gold)  it  is  known  as  Silicosis. 

(c)  Stone  grinders  it  is  known  as  Silicosis  or  Chalcicosis. 

(d)  Pottery  workers  it  is  known  as  Aluminosis. 

(e)  Iron  or  steel  grinders  it  is  known  as  Siderosis. 
if)  Tobacco  workers  it  is  known  as  Tobaccosis  and 
(g)   Cotton  workers  it  is  known  as  Byssinosis. 

The  degree  to  which  it  developes  among  workers  exposed  to 
hard  dust  is  very  high.     Ganister  disease  is  a  form  of  silicosis. 


Fig.  hi. — Grinding  iron  castings  on  emery  wheels.  The  dust-removal  sys- 
tem shown  is  effective  and  protects  the  workmen  to  a  great  extent  from  flying 
dust.      (Bull.  127,  Bur.  Labor  Stal.) 

The  men  are  engaged  in  making  the  brick  lining  for  smelters 
and  retorts.  Thus  per  one  thousand  men  in  the  ganister 
trade,  42.3  miners,  179.8  grinders  and  22.2  brickmakers  die  of 
silicosis.  In  the  zinc  mines  of  Joplin  Mo.  66  per  cent,  of  all 
miners  have  evidence  of  pulmonary  disease. 

The  available  remedies  are  based  upon  dust  removal  and 
reduction.  Thus  exhaust  ventilation  should  be  employed 
where  possible  and  the  workmen  required  to  use  respirators. 

Wetting  down  of  the  abrasive  work  and  wet  processes  should 
be  used  where  ever  possible.     (Fig.  in). 


254  PRACTICAL   PREVENTIVE    MEDICINE 

REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene.  3rd  Ed.,  pp.  1035-1075. 
Kober  and  Hanson:  Diseases  of  Occupation  and  Vocational  Hygiene. 
Hayhurst:  Industrial  Health  Hazards  and  Occupational  Diseases  in  Ohio. 

Ohio  State  Board  of  Health. 
Van  Schaack  :  Safeguards.     The  Aetna  Life  Insurance  Company. 
List  of  Industrial    Poisons.     Bull.    100.     Bureau  of  Labor.     Department  of 

Commerce  and  Labor. 
Dangers   to   Workers  from   Dust  and    Fumes  and    Methods  of    Protection 

Bull.  127,  Bureau  of  Labor  Statistics,  Dept.  of  Labor. 
Various  publications  of  the  Bureau  of  Labor  Statistics,  Dept.  of  Labor;  The 
Bureau  of  Mines,  Dept.  of  the  Interior;  and  The  Bureau  of  Public  Health  Service, 
Treasury  Dept.    Lists  can  be  secured  upon  request. 


SECTION  IV 

CHAPTER  XXVIII 
DISEASES  ARISING  FROM  THE  PUERPERAL  STATE 

In  the  registration  area  of  the  United  States,  there  occurred 
in  1916,  11,642  deaths  during  the  puerperal  state,  equivalent  to  a 
rate  per  100,000  of  16.3.     These  deaths  are  classified  as  follows: 

Accidents  of  pregnancy 985 

Puerperal  hemorrhage 1118 

Other  accidents  of  labor 1212 

Puerperal  septicemia 4786 

Puerperal  albuminuria  and  convulsions   .    .    .    .3087 
Puerperal  phlegmasia,  alba  dolens,  embolus  or 

sudden  death    .    . 415 

Following  childbirth  (not  otherwise  defined) ...  34 

Puerperal  diseases  of  the  breast 5 

During  the  period  from  1901  to  1905  the  annual  average  of  the 
death  rate  from  this  group  of  causes  was  14.2  per  100,000,  in 
the  next  five  year  period  it  was  15.5  and  during  1913,  15.8; 
1914,  15.9;  1915,  15-2.  In  general  it  has  shown  an  upward 
trend.  Few  classes  of  death  seem  more  tragic  or  pitiful  than 
these.  We  find  here  the  young  mother,  looking  forward  with 
joy  to  the  arrival  of  her  first  baby,  or  the  mother  of  a  family  of 
several  children,"  leaving  orphans,  broken  homes,  widowed 
fathers.  Probably  few  deaths  leave  as  great  a  load  of  sorrow 
as  do  these.  It  is  interesting  to  compare  the  losses  from  these 
causes  with  those  from  some  of  the  other  preventable  diseases; 
In  1916  typhoid  fever  caused  9,510  deaths;  measles  7,946, 
and  diphtheria  10,367.  If  these  rates  were  calculated  upon  the 
basis  of  100,000  women  they  would  approximately  be  doubled, 
and  be  still  higher  if  calculated  in  proportion  to  the  women  of 
childbearing  age.  A  still  more  accurate  idea  may  be  secured 
from  the  number  of  maternal  deaths  per  a  given  number  of 
births.  Data  on  this  point  can  only  be  given  for  1916  and  for 
the  birth  registration  area.     The  death  rate  per  1000  live  births 

255 


256 


PRACTICAL    PREVENTIVE    MEDICINE 


from  all  diseases  caused  by  pregnancy  and  confinement  is  6.5, 
from  puerperal  septicemia  2.9,  and  from  all  other  causes  3.6 
(Fig.  112). 

Of  these  deaths  the  most  numerous  are  from  puerperal  sep- 
ticemia. This  is  important,  for  of  the  above  causes  puerperal 
septicemia  is  the  least  excusable  as  its  preventable  character 
was  recognized  prior  to  the  bacteriologic  era.     Holmes  first 

MATERNAL  MORTALITY  THERMOMETER 

AVERAGE    DEATH  RATE    PER    100,000    POPULATION    FROM    CONDITIONS 
RELATED    TO  PREGNANCY    AND    CHILDBIRTH,  1900-1910 


22_ 


SWITZERLAND 

BOGIUM'1- 

AUSTRAUA- 

JAPAN- 

JTCW    ZEALAND- 


FTALY- 
N0RWAY- 


SWEDEN 3— 


^UNITED   STATES 

SCOTLAND 


EN6LAND  &  W4LES 

PRUSSIA 


The  United  States  lost  over  16000  women  in  1916  from 
childbirth.  We  have  a  higher  maternal  death  rate  than  ary 
other  of  the  principal  countries  except  Spain  or  Switzerlancl 

CHILDREN'S  BUREAU,  U.  S.  DEPARTMENT  OF  LABOR. 

Pig.   112. — (Bur.  Pub.  61.) 


pointed  out  in  1843  that  this  fever  was  similar  to  wound  infec- 
tions and  was  chiefly  due  to  the  carrying  of  infectious  material 
on  the  hands  of  attendants  from  one  case  to  another.  In  1847 
Semmelweiss  advanced  similar  ideas.  Previous  to  this  time 
the  mortality  from  puerperal  fever  in  maternity  hospitals  was 
appalling.  Subsequent  to  the  introduction  of  antiseptic 
treatment  the  mortality  immediately  fell  until  now  in  hospital 
practice  maternal  deaths  are  negligible  as  shown  in  the  table: 


DISEASES    ARISING    FROM    THE    PUERPERAL    STATE  257 

TABLE  X 


Year 

Hospital 

Place 

Confinements 

Deaths 

I9°7 

1907  (14  years  previous) 
1907-8 

Baudelocque  Paris 
Basle 
Rotunda        1  Dublin 

3,°34 

6,000 
2,060 

I.O 

o.oS 
3-o 

Yet  despite  the  demonstration  that  the  disease  is  unnecessary 
it  is  still  with  us  and  shows  no  apparent  diminution.  In  hos- 
pital practice  in  the  United  States  it  is  as  rare  as  indicated  by 
the  foreign  experiences,  but  among  home  confinements  it  is 
still  apparently  undiminished.  While  puerperal  septicemia 
is  undoubtedly  the  most  clearly  preventable  disease  of  this 
group,  yet  a  large  proportion  of  the  other  deaths  must  be 
regarded  as  due  to  preventable  causes. 

Nearly  80  years  ago  Holmes  showed  that  childbed  fever  was 
transmitted  from  patient  to  patient  by  the  hands  of  the  atten- 
dants. It  is  undoubtedly  true  that  obstetric  asepsis  is  drilled 
into  medical  students  the  country  over.  Why  then  these 
deaths?  A  formidable  proportion  of  confinements  in  some 
localities,  a  major  proportion  in  others,  are  not  attended  by 
physicians  but  by  mid  wives.  The  degree  to  which  the  assist- 
ance of  midwives  is  relied  upon  is  largely  proportional  to  the 
extent  of  the  foreign  born  population.  Thus  during  1916  in 
the  borough  of  Manhattan,  11,266  mothers  were  confined  in 
hospitals  and  institutions  and  47,384  in  their  homes.  Of  the 
latter,  19,524  or  41.4  per  cent,  were  attended  by  midwives. 
These  people  regard  the  service  of  a  physician  at  this  time  as  an 
unnecessary  expense.  The  majority  of  midwives  have  no 
special  qualifications  for  their  task  in  so  far  as  training  is  con- 
cerned. Most  can  handle  normal  confinements  but  if  complica- 
tions ensue,  call  in  a  physician.  They  have  no  idea  of  asepsis 
or  antisepsis,  make  unnecessary  and  frequent  vaginal  examina- 
tions and  introduce  unsterilized  instruments  as  well  as  unclean 
hands  into  the  parturient  canal.  The  knowledge  they  possess 
of  obstetrics  is  extremely  rudimentary  and  is  largely  acquired 
in  a  haphazard  manner,  never  from  competent  instruction. 
Is  it  any  wonder  that  puerperal  sepsis  is  still  with  us? 

It  probably  will  be  a  long  time  before  the  midwives  disappear. 
If  they  are  to  be  tolerated,  the  welfare  of  women  demands  that 
they  acquire  a  reasonable  competence  in  their  profession. 
Some  provision  should  be  made  for  their  formal  instruction  in 


258  PRACTICAL    PREVENTIVE    MEDICINE 

obstetrics  and  none  should  be  permitted  to  practice  without  a 
license  from  the  state.  Death  certificates  for  women  who  die 
in  the  puerperal  state  should  record  the  name  of  the  attendant 
during  the  confinement  and  those  who  show  a  disregard  for 
asepsis,  as  manifested  by  the  development  of  cases  of  septice- 
mia, should  be  barred  from  practice. 

Physicians  cannot  ignore  the  fact  themselves  that  the  instruc- 
tion that  medical  students  receive  in  obstetrics  and  obstetrical 
asepsis  is  inadequate.  We  cannot  belabor  the  mid-wife  and 
gloss  over  the  defects  in  our  own  practice  and  teaching. 

The  women  themselves  need  instruction  in  the  necessity 
for  good  care  at  the  time  of  confinement  and  prior  thereto. 
Husbands  must  learn  that  money  spent  to  safeguard  the  life  of 
their  wives  and  children  at  this  critical  time  is  spent  wisely 
and  for  a  stern  necessity.  Such  service  is  worth  a  respectable 
fee,  a  consideration  which  prevents  many  from  employing  the 
services  of  a  competent  physician  and  nurse.  Their  meager 
circumstances  only  permit  them  to  secure  the  uncertain  assist- 
ance of  a  mid-wife.  This  is  largely  a  problem  of  urban  popula- 
tions. The  best  solution  appears  to  be  through  the  agency  of 
prenatal  and  maternity  clinics. 

Prenatal  and  maternity  clinics  are  designed  for  the  welfare 
of  both  the  mother  and  child  who  without  assistance  would  not 
receive  adequate  care  prior  to,  during,  or  subsequent  to  con- 
finement. They  are  of  equal  value  in  the  elimination  of  infant 
mortality.  They  are  variously  maintained,  either  by  hospitals, 
philanthropic  organizations  or  health  authorities.  By  educa- 
tional propaganda  efforts  should  be  made  to  inform  women  of 
the  assistance  available  and  they  must  be  encouraged  to  present 
themselves  to  the  clinic  some  time  prior  to  confinement  for 
careful  examination.  If  serious  conditions  are  found  arrange- 
ments for  continuous  observation  and  care  must  be  made.  In 
any  event  the  prospective  mother  receives  instructions  in  the 
proper  physical  care  of  herself  and  in  making  suitable  arrange- 
ments for  her  anticipated  child.  Satisfactory  results  from 
attendance  during  the  prenatal  period  are  only  secured  where 
arrangements  permit  judicious  home  visiting  to  ascertain  that 
the  advice  given  has  been  understood  and  is  being  acted  upon. 
Advice  upon  diet,  clothing,  exercise  and  care  of  the  breasts  is 
especially  needed.  At  the  time  of  confinement  arrangements 
are  made  for  the  medical  care  of  the  mother  if  she  is  unable  to 
provide  for  it  herself,  or  if  the  presence  of  complications  necessi- 
tates hospital  care,  to  provide  admission  to  the  maternity  wards. 
The  prenatal  work  of  the  clinics  very  largely  relates  to  the 


DISEASES   ARISING   FROM   THE    PUERPERAL   STATE  259 

proper  care  of  the  infant,  and  as  such  will  be  considered  under 
infant  hygiene.  Co-ordinated  cooperation  with  other  chari- 
table agencies  is  frequently  necessary  to  enable  an  indigent 
mother  to  receive  proper  food. 

Another  group  of  women  in  entirely  different  circumstances 
usually  fail  to  receive  adequate  care  at  this  period.  Usually 
the  difficulty  is  not  a  question  of  good  or  bad  obstetric  care  or 
inability  to  provide  for  a  physicians  services,  but  rather  the 
inaccessibility  of  any  assistance  at  all  during  this  time.  This 
is  the  condition  which  many  women  in  rural  districts  must 
face,  particularly  in  the  extreme  north  and  west  where  pioneer 
conditions  prevail.  Many  children  are  born  with  no  other 
attendant  than  the  husband,  a  relative  or  neighbor.  The 
nearest  physician  may  be  located  many  miles  away  and  a 
hospital  many  miles  further.  With  inadequate  roads  and 
means  of  communication  it  is  not  possible  to  notify  the  physician 
in  time.  Under  these  circumstances  the  cost  of  a  physicians 
services  may  seem  unnecessarily  great  and  is  frequently  fore- 
gone. The  problem  of  these  women  is  difficult,  but  a  solution 
seems  available.  It  probably  can  satisfactorily  be  accom- 
plished along  these  lines; 

(a)  The  establishment  of  a  rural  nursing  service  centering 
at  the  county  seat,  with  nurses  especially  trained  to  discern 
the  danger  signs  of  pregnancy. 

(b)  An  accessable  county  center  for  maternal  and  infant 
welfare  at  which  mothers  may  obtain  simple  information  as  to 
the  proper  care  of  themselves  during  pregnancy  as  well  as  of 
their  babies. 

(c)  A  county  hospital  with  provision  for  maternity  cases, 
for  the  proper  care  of  abnormal  cases  and  of  normal  cases  when 
it  is  convenient  for  the  women  to  leave  their  homes  for 
confinement. 

(d)  Skilled  attendants  at  confinement  available  to  each 
woman. 

REFERENCES 

O.  W.    Holmes:  Puerperal    Fever,    The    Contagiousness   of,    Reprinted   in 

Carmac's  "  Epoch  Making  Contributions  to  Medicine,"  pp.  399. 
Maternal   Mortality  from  all  conditions  connected   with   Childbirth  in  the 

United  States  and  Certain  Other  Countries.     Bull.  6,  Misc.  series,  Children's 

Bureau,  Dept.  of  Labor. 
Maternity    Care  and   the  Welfare    of  Young   Children  in  a  Homesteading 

County  in   Montana.     Rural   Child   Welfare   Series,    Bull.   3,    Children's 

Bureau,  Dept.  of  Labor. 
The  Supervision    of    Midwives    in    New    York  City.     Mo.    Bull.    Dept.    of 

Health,  pp.  117,  May,  1919. 


SECTION  V 

CHAPTER  XXIX 

DISEASES  TRANSMITTED  FROM  PARENT  TO 
OFFSPRING 

Two  dissimilar  groups  of  diseases  are  here  considered.  The 
first  includes  those  diseases  due  to  infective  agents  in  which 
it  is  possible  for  an  invasion  of  the  germ  cells,  or  intrauterine 
infection  of  the  foetus,  to  occur.  Such  is  known  to  be  possible 
in  the  care  of  syphilis,  tuberculosis  and  small-pox.  However 
with  all  of  these  such  means  of  transmission  is  unusual,  and  is 
not  the  means  by  which  the  infection  is  perpetuated  in  the 
population  as  a  whole.  Such  transmission  is  of  greater  im- 
portance in  syphilitic  disease  than  in  the  other  two,  either  by 
reason  of  a  fatal  outcome  to  the  fetus,  or  a  permanent  injury 
to  those  which  do  happen  to  be  born  at  term.  These  infections 
from  a  public  health  standpoint  have  however,  already  been 
adequately  considered. 

The  second  group  comprises  the  true  examples  of  hereditary 
transmission  from  parent  to  offspring.  By  heredity  we  mean 
the  transmission  from  parent  to  offspring  through  the  germ 
cells  of  properties  inherent  or  characteristics  of  the  parent  or 
of  the  parental  stock.  By  disease  in  this  connection  we  have 
reference  to  any  departure  from  the  normal,  regarding  the 
normal  not  as  any  fixed  point,  but  as  the  limits  between  which 
any  particular  characteristics  of  the  majority  of  individuals  will 
fall. 

The  hereditary  diseases  in  the  strict  sense  may  be  divided  into 
groups  depending  upon  whether  or  not  their  transmission 
conforms  with  the  Mendelian  principles.  We  shall  first  con- 
sider those  which  conform  to  these  laws. 

DISEASES  TRANSMITTED  ACCORDING  TO  THE  MENDELIAN  INHERI- 
TANCE 

Before  considering  these  diseases  it  may  be  well  to  briefly 
review  the  more  salient  principles  of  mendelian  inheritance. 

260 


DISEASES    TRANSMITTED    FROM   PARENT    TO    OFFSPRING      26 1 

Its  principles  have  been  found  to  hold  true  for  all  forms  of  life 
and  we  can  perhaps  illustrate  it  most  conveniently  by  reference 
to  the  vegetable  kingdom. 

If  the  pollen  of  red  flowered  peas  (male)  is  employed  in 
fertilizing  the  ovaries  (female)  of  a  white  flowered  pea,  the 
mature  plants  which  develop  from  the  seeds  of  this  fertiliza- 
tion (hybrids)  are  all  red  flowering  like  their  male  parent. 
The  red  flowering  characteristic  is  stronger  in  leaving  its 
influence  upon  its  offspring  than  the  white  flowering  charac- 
teristic of  the  mother.  The  red  characteristic  is  therefore  said 
to  be  dominant  and  the  white  character  recessive.  The 
recessive  character  is  not  lost  in  the  first  generation  of  hybrids, 
but  is  only  latent,  as  we  shall  find  when  those  hybrids  are 
crossed  with  each  other.  The  offspring  of  those  hybrids  when 
brought  to  flower  will  not  all  be  found  similar  to  their  parents, 
but  will  be  arranged  in  groups  according  to  very  definite  rules. 
In  the  first  place  three  fourths  of  their  number  will  be  red  flow- 
ered, i.e.,  present  the  dominant  characteristic,  while  one- 
fourth  will  be  white  flowered,  that  is,  present  the  recessive 
character.  The  two  groups  are  in  a  ratio  of  3  :  1,  sometimes 
called  the  Mendelian  ratio.  If  now  then  like  individuals  of 
the  third  generation  be  crossed  with  each  other,  it  will  be  found 
that  among  the  progeny  of  the  white  flowers,  only  white 
flowered  offsprings  will  occur  in  the  fourth  generation.  On  the 
other  hand,  of  the  progeny  of  the  red  flowers,  one  fourth  will 
be  as  red  as  the  original  male  parent,  while  one  half  will  be 
less  clearly  red  and  show  clearly  that  they  are  hybrids,  and 
one-fourth  will  be  white.  Thus  of  the  fourth  generation, 
one-fourth  will  present  only  the  dominant  characteristic,  one- 
fourth  the  recessive  character  and  the  remaining  half,  though 
appearing  like  the  dominant,  possess  the  properties  of  hybrids. 
(Fig.  113). 

One  may  designate  by  the  term  determiner  the  unknown 
substance  in  the  germ  cells  which  determines  in  some  way  the 
different  characteristics  of  an  individual,  such  as  the  color  of 
the  skin,  the  kind  of  hair,  mental  traits,  etc. 

If  each  of  two  parents  possess  a  given  character  and  each  one 
transmits  the  determiner  for  that  character  to  their  offspring, 
then  the  offspring  will  possess  two  determiners  for  a  given 
character,  one  from  each  parent.  Then,  unless  there  is  some- 
thing to  prevent  it,  this  offspring  will  in  turn  transmit  two 
determiners  to  its  progeny.  If  the  other  parent  of  this  genera- 
tion  also   contributes   two   determiners   the   third  generation 


262 


PRACTICAL    PREVENTIVE    MEDICINE 


will  possess  four  determiners  for  each  character  and  so  the  num- 
bers of  determiners  would  multiply.  This  however  is  prevented 
by  the  division  of  the  chromosomes  in  the  germ  cell  before 
maturity  is  reached,  in  which  it  is  assumed  the  determiners 
reside.     Thus  only  one  half  of  the  determiners  pass  into  each 


vM 


"4, 


RR=. 
DR=  t 

dd4 

»*-3 


(  r r  J    rr  r  DR J  DP  nv&Rj  OR  i  ^ D  j  D D  ■ 


and  so  on 
amond  the  hybrids 


1 


H 


n 


i? 


One  half  normal  All  normal 

R=Recesstve  trait 
P=Dominant"  trait 

5Rl|  Duplex,  pure 
pfc  Simplex.,  Hybrid 

Fig.   113. — Mendelian  inheritance. 

mature  germ  cell  and  there  is  actually  no  increase.  Therefore 
in  the  union  of  hybrid  germ  cells  each  containing  one  deter- 
miner for  a  given  character,  the  determiners  unite  and  depend- 
ing upon  whether  they  are  similar  or  dissimilar,  dominant  or 
recessive,  the  offspring  will  according  to  our  example,  be  either 
like  the  dominant  male  plant,  the  recessive  female  plant,  or 


DISEASES    TRANSMITTED    FROM   PARENT    TO    OFFSPRING      263 

the  hybrids,  which  possess  both  the  dominant  and  recessive 
determiners  alone.  The  former  we  can  designate  as  a  duplex, 
the  latter  (the  hybrids)  as  simplex  combinations  of  deter- 
miners. Now  when  an  individual  who  appears  normal  but  has 
the  dominant  determiner  in  duplex  is  united  with  a  hybrid, 
two  kinds  of  offspring  may  result.  One  half  will  have  the 
dominant  character  in  simplex  and  one  half  in  duplex  but  all 
will  appear  as  normal.  On  the  other  hand  if  an  individual 
with  a  recessive  determiner  in  duplex,  is  united  with  a  hybrid 
with  one  dominant  and  one  recessive  determiner,  two  kinds  of 
offspring  are  likewise  possible.  One  half  will  have  one  domi- 
nant and  one  recessive  character  each  (simplex)  but  appear 
like  the  normal  who  has  the  dominant  character  in  duplex  and 
one  half  will  have  the  recessive  character  in  duplex  and  will 
not  appear  true  to  the  normal  type.     (Fig.  113). 

Certain  diseases  appear  to  be  transmitted  from  parent  to 
offspring  by  either  dominant  or  recessive  characteristics  of  the 
germ  plasm.     Their  characteristics  are  briefly  presented. 

(a)  Huntington's  chorea  is  a  condition  in  which  there  are 
marked  involuntary,  irregular  contractions  of  the  muscles 
leading  to  a  more  or  less  constant  movement  of  the  limbs. 
There  is  also  dementia.  It  begins  in  middle  life,  affects  both 
sexes  about  equally  and  is  usually  transmitted  whenever  present 
in  either  parent.  It  is  therefore  a  dominant  trait.  Many  of 
the  cases  in  this  country  are  traceable  to  several  families 
belonging  to  an  old  New  England  colony. 

(b)  Albinism  refers  to  a  condition  in  which  there  is  an  absence 
of  pigment  from  the  skin,  hair  and  eyes,  a  condition  seen  in 
white  mice  or  rabbits.  It  is  rare  in  man.  It  is  undesirable 
since  the  lack  of  pigment  makes  the  skin  and  eyes  very  sensitive 
to  light.     It  is  a  typically  recessive  condition. 

(c)  Deaf-Mutism  refers  to  a  kind  of  deafness  which  begins 
early  in  life  before  the  power  of  speech  has  been  acquired,  hence 
these  individuals  can  neither  hear  nor  speak.  Fay  has  exten- 
sively studied  this  inheritance.  Of  335  matings  of  congenitally 
deaf  parents,  25  per  cent,  yielded  deaf  offspring.  A  total  of 
779  children  were  born  of  whom  26  per  cent,  were  deaf.  That 
all  children  of  such  marriages  are  not  deaf  is  doubtless  due  to  the 
fact  that  the  parents  are  not  deaf  in  the  same  way  and  one 
parent  brings  into  the  combination  something  which  the  other 
lacks. 

(d)  Insanity  may  result  from  various  causes.  Some  cases 
are  the  result  of  organic  brain  disease.     Such  are  not  inheritable. 


264  PRACTICAL    PREVENTIVE    MEDICINE 

On  the  other  hand  with  functional  insanity  without  well  defined 
lesions,  some  evidence  of  heredity  is  available.  It  is  the 
tendency  to  insanity  or  the  neuropathic  trait  which  is  inherited. 
It  follows  the  laws  of  heredity  governing  recessive  characters. 

(e)  Feeble  Mindedness  like  insanity  in  many  instances  is  a 
recessive  trait.  It  is  not  always  easy  to  determine  who  is  and 
who  is  not  a  feeble  minded  individual.  At  one  end  of  the 
scale  we  have  those  who  are  exceptionally  able.  In  a  general 
way  we  may  say  that  a  child  is  feeble  minded  who  for  no  obvious 
reason  at  the  age  of  ten  is  no  further  advanced  in  his  school 
work  than  are  other  children  at  the  age  of  six  or  seven.  Within 
normal  variations  we  may  have  children  one  or  two  years 
behind  or  in  advance  of  the  average. 

Mendel's  law  is  also  exemplified  by  what  are  known  as  sex- 
limited  diseases,  examples  of  which  are  color  blindness  and 
hemophilia.  These  are  diseases  that  appear  almost  only  in 
the  male  line,  but  are  transmitted  only  through  the  female 
line.  Thus  if  a  given  man  be  affected,  his  sons  will  not  have 
the  disease  nor  will  they  transmit  it  to  their  offspring,  nor  will 
his  daughters  have  the  disease,  but  they  will  transmit  it  to  their 
sons.  The  explanation  of  this  is  associated  with  the  deter- 
miner from  the  male  chromosome.  Striking  examples  of  this 
type  of  heredity  are  observed  with  multiple  sclerosis,  atrophy 
of  the  optic  nerve,  color  blindness,  myopia,  ichthyosis,  muscular 
atrophy  and  hemophilia. 

DISEASES  NOT  CONFORMING  TO  MENDEL'S  LAW 

(a)  Friedreich's  ataxia  begins  in  childhood  and  usually  occurs 
in  a  family  having  other  members  similarly  affected  There  are 
curious  forms  of  incoordination,  loss  of  knee-jerk,  early  talipes 
equinus,  scoliosis/  nystagmus  and  scanning  speech.  Since 
it  has  usually  been  observed  as  a  family  disease  it  is  assumed  to 
be  transmitted  hereditarily. 

(b)  Reversionary  inheritance  does  not  appear  to  follow  the 
Mendelian  laws.  It  represents  a  return  of  the  offspring  to  a 
lower  type,  a  development  which  is  incomplete  and  corresponds 
to  a  stage  characteristic  of  an  earlier  period  in  the  development 
of  the  species,  whether  affecting  the  body  as  a  whole,  or  only 
some  particular  portion,  such  as  the  nervous  system.  The 
typical  degenerate  is  of  poor  bodily  development,  the  brain  is 
smaller  than  normal,  with  convolutions  less  abundant  and  less 
fully  formed,  possesses  a  degraded  physiognomy,  little  capacity 


DISEASES    TRANSMITTED    FROM   PARENT    TO    OFFSPRING      265 

for  sustained  attention  or  prolonged  thought,  is  cunning  rather 
than  intelligent,  is  deficient  in  a  moral  sense;  in  all  these 
characteristics  resembling  the  lower,  less  developed  types  of 
our  own  species.  Thus  this  type  of  inheritance  is  the  reasser- 
tion  of  properties  which  have  remained  latent. 

NATURAL  IMMUNITY 

Immunity  is  either  natural  or  acquired.  The  former  is 
inherited  through  successive  generations  in  a  species  or  race. 
Acquired  immunity  does  not  appear  to  be  a  transmissible 
characteristic,  at  least  to  such  an  extent  that  changes  are 
rapidly  observable  in  the  span  of  a  few  generations. 

EUGENICS 

Eugenics  is  the  science  of  the  improvement  of  the  human 
race  by  better  breeding.  The  success  of  a  marriage  from  the 
standpoint  of  eugenics  is  measured  by  the  number  of  normal, 
cultivable  offspring  that  arise.  It  has  to  deal  with  traits  that 
reside  in  the  germ  plasm.  The  superstition  of  pre-natal  in- 
fluence and  the  effects  of  venereal  disease  lie  outside  the  scope 
of  eugenics. 

In  the  foregoing  paragraphs  we  have  only  sketched  the 
hereditary  transmission  of  certain  undesirable  qualities.  If 
space  permitted,  a  similar  sketch  of  the  hereditary  transmission 
of  desirable  qualities  could  be  presented.  It  is  these  eugenics 
desires  to  augment  and  to  eliminate  the  undesirable.  The 
science  is  in  its  infancy  at  present  and  our  knowledge  is  but 
fragmentary.  Some  progress  can  be  made  among  those  of 
intelligence  by  propaganda  explaining  the  known  facts.  Un- 
fortunately among  those  possessing  many  undesirable  charac- 
teristics such  means  of  propaganda  is  impossible.  Appeals 
cannot  be  made  to  the  degenerate,  to  the  criminal,  to  the  feeble 
minded.  The  elimination  of  the  hereditary  traits  of  this  char- 
acter require  the  united  action  of  society  to  stop  the  procreation 
of  those  who  are  unfit  by  reason  of  defective  germ  plasm.  No 
real  progress  has  been  made  in  this  direction  but  in  some  places 
a  creditable  start  has  been  made. 

Prohibition  of  the  marriage  of  those  possessing  socially 
undesirable  characteristics  will  not  prevent  the  illegitimate 
procreation  of  such  individuals.  Such  laws  are  manifestly 
inadequate.     A  solution  that  has  been  legally  adopted  in  some 


266  PRACTICAL   PREVENTIVE   MEDICINE 

states  is  that  of  sterilization,  but  its  enforcement  has  been 
limited.  There  is  no  question  but  that  such  a  procedure  applied 
to  all  the  feeble  minded,  the  epileptic,  insane  or  criminal  persons 
in  the  country  would  produce  an  enormous  reduction  in  the 
institutional  population  in  the  course  of  a  generation.  The 
greatest  difficulty  lies  in  the  satisfactory  definition  or  accurate 
recognition  of  those  whose  procreative  abilities  should  be  sacri- 
ficed to  the  social  welfare.  An  alternative  solutionis  the  segre- 
gation in  institutions  of  such  persons  until  the  reproductive 
period  has  passed.     We  could  expect  the  same  results. 

On  the  other  hand,  there  is  the  group  composed  of  those 
having  defects  not  inimical  to  society.  Some  of  those  traits 
may  involve  the  possession  of  severe  handicaps,  and  it  is  per- 
haps better  that  such  traits  should  become  extinct.  More 
satisfactory  results  in  this  direction  can  perhaps  be  accom- 
plished through  the  persuasive  powers  of  the  family  physician 
in  whom  the  afflicted  individual  has  confidence.  The  necessity 
or  desirability  for  celibacy  can  be  judged  from  the  type  of 
undesirable  trait  presented  and  a  knowledge  of  the  type  of 
Mendelian  inheritance  followed. 

REFERENCES 

Davenport:  Heredity  in  Relation  to  Eugenics. 

Rosenau:  Preventive  Medicine  and  Hygiene,  3rd.  ed.  pp.  470-515. 

Mental  Hygiene,  Reprint  164,  Public  Health  Reports. 

Overton  and  Denno.    "The  Health  Officer."    Chapter  XXX. 


SECTION  VI 

SPECIAL  ASPECTS  OF  HYGIENE  AND 
SANITATION 

CHAPTER    XXX 
HYGIENE  OF  INFANCY 

The  age  period  of  infancy  includes  all  those  under  the  age  of 
one  year.  This  undoubtedly  is  the  most  critical  period  of  life, 
during  which  the  newly  born  is  adapting  itself  to  a  new  en- 
vironment. It  is  not  surprising  that  many  have  a  great  deal 
of  difficulty  in  meeting  the  changed  conditions  encountered 
after  birth  and  die.  The  deaths  during  the  first  year  of  life 
are  higher  than  at  any  subsequent  age  period  (Fig.  113a). 
In  1 9 10  they  amounted  to  20  per  cent,  of  all  the  deaths  in  the 
registration  area.  Ten  per  cent,  of  all  deaths  during  the  first 
year  occur  in  the  first  day  of  life  and  25  per  cent,  during  the 
first  month.  Roughly  8  per  cent,  of  infants  born  die  during 
the  first  month  of  life.  The  proportion  of  all  born  which  die 
during  the  first  year  of  life  varies  from  10  to  35  per  cent.  From 
birth  there  is  a  steady  decline  in  the  mortality  throughout  the 
first  year  and  when  the  second  year  is  reached  the  mortality  is 
only  one-fifth  of  what  it  was  in  the  preceding  year.  In  recent 
years  the  deaths  during  this  age  period  have  been  steadily 
falling.  One  or  two  hundred  years  ago  they  were  simply 
appalling,  even  in  the  highest  society.  The  appalling  character 
of  this  mortality  is  heavily  emphasized  when  we  consider  that 
a  larger  proportion,  probably  the  majority  of  these  deaths  are 
preventable  (Fig.  114). 

THE  CAUSES  OF  INFANT  MORTALITY  MAY  BE  ROUGHLY  PLACED  IN 

SIX  GROUPS 

The  first  of  these  includes  the  deaths  due  to  prematurity, 
congenital  defects  and  debility,  and  to  accidents  at  birth.  They 
are  responsible  for  about  25  per  cent,  of  the  deaths.     These  are 

267 


268 


PRACTICAL    PREVENTIVE    MEDICINE 


largely  due  to  parental  influences,  to  diseases  of  the  parents, 
such  as  syphilis  and  gonorrhea,  alcoholism,  overwork  of  the 
mother  during  the  latter  portion  of  the  pregnancy,  eclampsia, 
pelvic  deformities  and  the  maladministrations  of  incompetent 
mid-wives.  Many  of  these  are  associated  with  the  death  of  the 
mother.  While  the  majority  of  the  deaths  in  this  group  are 
not  directly  due  to  preventable  causes,  yet  a  considerable  por- 


INFANT  MORTALITY  THERMOMETER 

DEATHS  UNDER  1  YEAR  OF  AGE   PER  1,000  BIRTHS 


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Within  the  first  year  after  birth,  the  United 
States  loses  linlO  of  all  babies  born.  It  ranks 
eleventh  among  the  principal  countries  of  the  world. 
New  Zealand  loses  fewer  babies  than  an/ other  country 

Rates   are  for   latest   available    years  up  to  1916.  "^ 

CHILDREN'S  BUREAU,  U.  S.  DEPARTMENT  OF  LABOR. 

Pig.  113,  a. — (Bur.  Pub.  61.) 

tion  must  be  regarded  as  due  to  causes  which  are  indirectly 
preventable. 

The  second  group  comprises  the  nutritional  disturbances  and 
the  acute  gastro-intestinal  diseases.  These  are  responsible  for 
about  35  per  cent,  of  the  mortality.  These  must  be  regarded 
as  primarily  due  to  bad  feeding.  This  fact  is  emphasized  by 
rinding  that  85  per  cent,  of  infantile  deaths  are  among  the 
bottle  fed  and  further  that  90  per  cent,  of  the  deaths  from 


HYGIENE    OF   INFANCY 


269 


diarrheal  diseases  are  among  those  fed  from  the  bottle.  Bad 
feeding  of  infants  is  largely  a  question  of  artificial  feeding,  so 
as  a  consequence  we  must  regard  all  deaths  in  this  group  as 
preventable.  Closely  associated  with  bad  feeding  is  the  in- 
fluence of  hot  summer  temperatures,  which  not  only  exercises 
a  directly  injurious  influence  on  the  baby,  but  also  on  the 
keeping  qualities  of  his  food. 

The  third  group  includes  the  acute  respiratory  infections, 
bronchitis,  bronchopneumonia  and  lobar  pneumonia.     These 


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Fig.  114. — Infantile  mortality  (deaths  of  infants  under  1  year  of  age  per 
IOOO  births  per  annum  exclusive  of  stillbirths).  German  Empire,  France, 
England  and  Wales,  Denmark,  Sweden,  and  New  Zealand — 1892  to  ioir. 
(Trask:  Suppl.  12.     P.  H.  Rep.) 

produce  about  20  per  cent,  of  the  deaths.     They  largely  arise 
as  a  result  of  overcrowding  or  bad  ventilation. 

The  fourth  group  includes  the  acute  infectious  diseases. 
These  at  this  age  period  are  of  lesser  importance,  causing  only 
about  3  per  cent,  of  the  deaths.  Whooping  cough  is  the  prin- 
cipal member  of  this  group  as  far  as  infants  are  concerned. 
Fifty-seven  per  cent,  of  the  deaths  from  whooping  cough  occur 
during  the  first  year  and  23  per  cent,  during  the  second  year. 
An  infant  is  susceptible  from  birth  to  whooping  cough.     To- 


270  PRACTICAL   PREVENTIVE    MEDICINE 

ward  many  of  the  other  acute  infections  an  infant  presents  a 
considerable  immunity  which  persists  for  several  months. 

Tuberculosis,  chiefly  meningeal  in  type,  causes  about  2  per 
cent,  of  the  deaths.  Infants  should  not  come  in  contact 
with  adults  having  open  lesions  of  tuberculosis,  nor  be  fed  upon 
the  milk  of  tuberculous  cows. 

Syphilis  causes  only  about  1  per  cent,  of  the  deaths.  It 
operates  chiefly  as  a  cause  of  prematurity  and  miscarriages. 

Nearly  everywhere  infant  mortality  is  greatest  in  the  most 
unsanitary  and  crowded  areas.  As  a  consequence  the  extent 
of  infant  mortality  is  a  good  index  of  sanitary  conditions. 

THE  INSTITUTIONAL  CARE  OF  INFANTS 

The  infant  that  is  doomed  to  institutional  care  has  very  poor 
prospects  in  life.  The  majority  are  illegitimates  and  hence  are 
unwelcome.  While  the  mortality  in  institutions  is  high  even 
with  the  best  of  care  and  the  employment  of  wet  nurses,  while 
without  wet  nurses  it  may  reach  100  per  cent. 

The  following  factors  are  principally  responsible  for  this 
appalling  mortality:  (1)  The  institutions  are  usually  over- 
crowded, so  that  respiratory  infections  run  like  wild  fire;  (2) 
There  is  a  lack  of  sufficient  fresh  air ;  (3)  Respiratory  infections, 
whose  dissemination  is  favored  by  overcrowding  and  defective 
ventilation,  and  lastly,  (4)  The  lack  of  mothering.  Babies 
thrive  best,  other  things  being  equal,  where  they  receive  a  great 
deal  of  individual,  personal  attention.  They  seem  to  require 
encouragement  and  coaxing  over  the  period  of  their  adaption 
to  extra-uterine  life. 

The  following  conditions  will  largely  reduce  the  mortality 
among  this  class  of  infants.  Every  effort  should  be  made  to 
induce  the  mother  to  keep  her  child.  Its  chances  of  survival 
are  enormously  improved,  even  though  it  is  later  placed  in  an 
institution.  Institutions  for  the  care  of  infants  are  usually 
privately  conducted  and  commonly  known  as  "Baby  Farms" 
or  boarding  houses.  These  should  be  placed  under  the  control 
and  supervision  of  health  authorities,  so  that  abuses  in  their 
conduct  may  be  eliminated.  For  this  purpose  their  licensure 
is  necessary.  A  practice  that  is  preferable  to  the  employment 
of  boarding  houses  is  that  of  boarding  the  babies  in  private 
families  with  wet  nursing.  This  enables  the  infant  to  receive 
the  necessary  individual  attention.  Infant  hospitals  should 
be  only  for  those  acutely  sick  and  should  not  partake  of  the 


HYGIENE    OF    INFANCY  27 1 

character  of  boarding  houses.  As  soon  as  possible  the  child 
should  be  returned  home.  Every  hospital  which  cares  for 
infants  should  be  provided  with  wet  nurses.  Wassermann. 
tests  should  be  made  on  both  infant  and  nurse  to  prevent  the 
transfer  of  luetic  virus  in  either  direction. 

BREAST  FEEDING 

Breast  feeding  is  essential  to  the  really  proper  welfare  of  an 
infant.  Its  value  is  seen  from  the  fact  that  breast  fed  infants 
seldom  suffer  from  intestinal  troubles.  The  extent  to  which 
breast  feeding  is  practiced  varies  in  different  countries,  districts 
of  cities  and  with  different  races  and  customs.  Thus  in  191 1 
in  Boston,  only  68  per  cent,  of  the  infants  were  breast  fed.  It 
is  possible  to  increase  this  proportion.  Various  causes,  some 
justifiable,  are  responsible  for  the  failure  of  some  mothers  to 
breast  feed  their  offspring.  Some  are  deliberately  unwilling 
and  regard  it  as  an  annoyance,  while  others  do  not  appreciate 
its  importance  from  the  standpoint  of  their  child's  welfare. 
Others  have  to  work  away  from  home  under  conditions  that 
do  not  permit  them  to  take  their  child.  Some  are  physically 
unable  to  nurse  because  of  lack  of  milk.  The  glittering  ad- 
vertisements of  proprietary  foods  lead  others  astray. 

These  obstacles  can  largely  be  overcome.  Pregnant  and 
nursing  women  must  be  educated  in  the  importance  of  breast 
feeding.  Certain  classes  of  mothers,  especially  those  whose 
children  most  require  assistance,  can  be  reached  through  pre- 
natal clinics  and  child  welfare  conferences.  Employers  of 
married  women  should  make  provision  for  mothers  to  bring 
their  babies  to  work.  Indigent  mothers  who  are  unable  to 
secure  sufficient  food  for  themselves,  let  alone  a  baby  in  addi- 
tion, require  charitable  assistance. 

ARTIFICIAL  FEEDING 

If  artificial  feeding  is  properly  carried  out  most  babies  will 
thrive  upon  it.  The  difficulty  lies  in  the  fact  that  it  is  fre- 
quently, if  not  usually,  improperly  carried  out.  Difncuties 
arise  from  the  fact  that  a  poor  grade  of  cows  milk  may  be  the 
only  milk  available,  improper  modifications  may  be  employed, 
the  milk  may  be  inadequately  kept  or  is  spoiled  and  the  bottles 
and  nipples  may  be  neglected. 

Proper  artificial  feeding  requires  the  following  conditions. 


272 


PRACTICAL  PREVENTIVE  MEDICINE 


An  adequate  supply  of  either  pure  raw  cows  milk  of  certified 
grade  or  pasteurized  milk  must  be  available.  Charitable 
organizations  should  make  provisions  either  for  its  free  distri- 
bution or  its  distribution  at  a  reduced  price  to  indigent  mothers. 
Similarly  ice  supplies  for  its  proper  keeping  in  the  home  should 
also  be  available.  In  the  absence  of  regular  refrigerators,  sim- 
ple devices  can  be  employed  for  the  refrigeration  of  the  milk. 
Attention  has  been  called  to  these  in  the  section  on  milk. 
Mothers  should  be  instructed  in  the  proper  care  of  the  milk  and 
of  nursing  bottles.  Proper  modification  of  the  milk  is  essen- 
tial. Many  physicians  are  not  familiar  with  proper  procedures 
for  the  adaption  of  cows  milk  to  infant  feeding.  Proper 
education  of  physicians  in  these  procedures  in  order  that  they 
may  in  turn  properly  instruct  their  patrons  is  necessary. 
Parents  may  also  be  instructed  in  milk  modification  at  pre- 
natal clinics  and  child  welfare  centers. 

CHARITIES  AND  CLINICS 

We  have  already  called  attention  to  the  value  of  prenatal 
clinics  in  the  education  of  expectant  mothers.     These  organiza- 


FiG.  115. — Everything  prepared  for  a  demonstration  of  baby  care  (Stamford, 
Conn.).  Such  demonstrations  are  of  great  value  in  educating  mothers  in  infant 
care.      (Children's  Bureau  Pub.  15.) 


tions  are  scarcely  of  less  benefit  in  the  education  and  supervis- 
ion of  mothers  after  the  birth  of  the  baby  than  they  were  before 


HYGIENE    OF   INFANCY  273 

the  event.  Advice  and  assistance  on  all  subjects  relating  to 
the  child's  welfare  is  given.  Child  welfare  centers  offer  similar 
assistance  and  instruction  (Fig.  115). 

Many  notable  milk  charities  have  been  organized.  These 
provide  satisfactory  modified  milk  at  a  cheap  price  or  free  of 
charge. 

Of  inestimable  value  in  the  education  of  mothers  and  in 
the  reduction  of  infant  mortality  are  the  services  of  visiting 
nurses.  These  women  serve  either  under  the  auspices  of  some 
local  philanthropic  organization  or  the  local  health  authorities. 
Their  principal  work  is  in  the  infant's  home.  It  is  in  this  con- 
nection that  the  prompt  registration  of  births  is  of  great  value 
in  the  control  of  infant  mortality.  These  nurses  visit  all 
homes  from  which  births  are  reported  within  a  week  or  ten 
days.  They  ascertain  if  the  mother  needs  advice  or  assistance. 
This  if  required  is  given,  or  if  financial  assistance  is  necessary 
they  direct  the  mother  to  the  proper  source  of  the  needed  help. 
Regular  follow  up  visits  are  made  to  see  if  the  mother  is  properly 
carrying  out  the  advice.  Women  for  successful  work  in  this 
field  must  possess  a  great  deal  of  tact  and  diplomacy.  The 
results  of  this  work  are  exceedingly  beneficial. 

HEAT 

The  extreme  heat  of  the  summer  months  makes  this  period 
very  trying  for  infants.  This  is  especially  true  where  the 
effects  of  the  heat  are  exaggerated  by  overcrowding,  by  reflected 
and  absorbed  heat  from  buildings  and  pavings,  and  where 
ventilation  is  inadequate.  It  exercises  a  directly  depressing 
effect  on  a  child's  vitality.  The  heat  also  prompts  the  growth 
of  putrefactive  bacteria  in  the  child's  milk,  which  tends  to 
increase  the  frequency  of  digestive  disturbances.  An  abun- 
dance of  flies  and  the  absence  of  fly  protection  assist  in  the 
spread  of  diarrhea  and  dysentery.  Great  care  should  be  given 
the  child's  food,  it  should  be  kept  as  cool  as  possible  and  pro- 
tected from  flies.  Furthermore  many  mothers  constantly 
overclothe  their  babies  during  the  summer. 

INFECTIONS 

We  may  call  attention  again  to  several  communicable 
diseases  of  especial  importance  to  infants.  First,  the  severity  of 
whooping-cough.     Second,  that  ophthalmia  neonatorum  which 


274  PRACTICAL  PREVENTIVE  MEDICINE 

causes  about  one-fourth  of  all  blindness,  can  be  effectively 
avoided  by  the  employment  of  Crede's  method  of  prevention 
with  silver  nitrate.  And  lastly  small-pox  vaccination  is  best 
given  for  the  first  time  in  the  first  year  before  the  second  sum- 
mer. It  may  be  safely  given  when  the  child  is  one  month  old 
with  less  discomfort  than  an  adult  experiences. 

REFERENCES 

Birth  Registration:  an  aid  in  protecting  the  lives  and  rights  of  children. 
Monograph    i,  Children's  Bureau,  Dept.  of  Labor. 

Handbook  of  Federal  Statistics  of  Children.  Pub.  5,  Children's  Bureau. 
Dept.  of  Labor. 

A  Tabular  Statement  of  Infant -Welfare  Work  by  Public  and  Private  Agen- 
cies in  the  United  States.     Pub.  16,  Children's  Bureau,  Dept.  of  Labor. 

Infant  Care.     Pub.  8,  Children's  Bureau,  Dept.  of  Labor. 

Child's  Welfare  Exhibits.     Pub.  14,  Children's  Bureau,  Dept.  of  Labor. 

Baby-week   Campaigns.     Pub.    15,    Children's   Bureau,   Dept.   of  Labor. 

Baby  Saving  Campaigns.     Pub.  3,   Children's  Bureau,  Dept.  of  Labor. 

Summer  Care  of  Infants.     Supplement  16,  Public  Health  Reports. 

Heat  and  Infant  Mortality.     Reprint  155,  Public  Health  Reports. 

Also  various  studies  of  infant  mortality  in  Waterbury,  Conn.,  Johnstown,  Pa., 
Manchester,  N.  H.,  Montclair,  N.  J.,  and  Brockton.  Mass.,  published  separately 
by  the  Children's  Bureau. 


CHAPTER  XXXI 

HYGIENE  OF  CHILDHOOD 

By  the  term  childhood  we  refer  to  the  age  period  from  infancy 
to  puberty.  As  measured  by  the  death  rate,  this  is  the  most 
hardy  period  of  life,  being  less  than  at  any  other  age  period. 
The  hygienic  development  of  the  child  during  this  period  is 
indirectly  of  great  importance  as  it  will  profoundly  influence 
the  physical  welfare  of  the  individual  as  an  adolescent  and 
adult.  We  will  briefly  consider  the  more  salient  of  the  hygienic 
hazards  which  confront  the  child: 

COMMUNICABLE  DISEASES 

During  the  months  immediately  following  birth  there  is  a 
temporary  immunity  toward  measles,  scarlet  fever  and  diph- 
theria. This  disappears  during  infancy,  so  that  by  the  time 
childhood  is  reached  the  individual  is  susceptible  to  nearly 
all  of  the  acute  infections.  Thus  we  find  that  certain  diseases 
have  their  greatest  age  incidence  at  this  period  of  life,  namely, 
measles,  german  measles,  mumps,  chicken  pox,  diphtheria, 
scarlet  fever,  poliomyelitis,  meningococcic  meningitis,  etc. 
This  peculiar  maximum  may  perhaps  be  due  to  either  or  both 
of  the  following  factors,  namely  (i)  to  the  susceptibility  of  the 
children,  or  (2)  to  the  greater  opportunities  which  exist  among 
children  for  the  transfer  of  infective  secretions  by  the  agencies 
of  contact.  On  the  other  hand,  infection  with  Mycobacterium 
tuberculosis,  whose  presence  is  most  commonly  manifested 
by  clinical  tuberculosis  during  adolescence  and  early  adult  life, 
is  received  during  childhood. 

ORTHOPEDIC  DEFECTS 

These  are  deformities  arising  from  faulty  posture,  and  the 
types  we  shall  consider  are  functional  in  character.  They 
chiefly  arise  as  a  result  of  prolonged  periods  of  seating,  such  as  a 
child  is  forced  to  maintain  at  school. 

(a)  The  most  common  of  these  is  the  so-called  "Round 
Back."     It  is  manifested  by  a  prominent  abdomen,  a  back- 

275 


276  PRACTICAL  PREVENTIVE  MEDICINE 

ward  convexity  of  the  spine,  a  contracted  chest  and  a  ptosis  of 
the  viscera.  The  foot  is  usually  everted  outwards.  It  gives 
the  individual  the  appearance  of  leaning  backwards.  Its 
contributing  causes  include  poor  nutrition,  hard  physical  work 
and  poor  postures.  Its  development  is  assisted  by  poor  cloth- 
ing such  as  the  continuous  drag  which  elastic  garters  exert 
when  suspended  from  the  shoulders.  It  may  be  remedied  by 
properly  suspended  clothing,  by  proper  seats  and  the  inaugura- 
tion of  relaxation  periods  which  include  setting  up  exercises. 

(b)  The  second  group  includes  the  functional  lateral  devia- 
tions or  scoliosis.  All  functional  scolioses  are  single  curva- 
tures of  the  spine.  The  most  common  type  is  where  the  con- 
vexity of  the  spine  is  to  the  left.  These  produce  an  elevation 
of  the  right  crest  of  the  ileum,  a  waist  line  indented  more  on  the 
concavity  (right  side)  of  the  curve,  the  opposite  (left)  shoulder 
is  higher  and  rotated  forward,  the  right  (concave)  side  is  seen 
to  be  higher  or  more  prominent.  With  deviation  to  the  right, 
which  includes  only  about  10  per  cent,  of  the  cases,  the  above 
conditions  are  reversed.  All  of  the  above  conditions  must  be 
observed  for  a  diagnosis.  It  is  correctable  by  proper  gymnastic 
exercises,  but  if  uncorrected  may  lead  to  structural  changes. 

OCULAR  HYGIENE 

The  ocular  conditions  of  greatest  importance  during  child- 
hood include  the  acute  infections  and  eye  strain.  Among  the 
former,  various  forms  of  acute  conjunctivitis  and  trachoma 
are  of  importance.  School  and  household  epidemics  of  these 
are  not  unusual,  due  to  the  exchange  of  infective  secretions  by 
contact.  While  acute  conjunctivitis  may  lead  to  a  permanent 
impairment  of  vision,  trachoma  is  of  far  greater  importance  and 
less  easy  to  control. 

Eyestrain  or  defective  vision  may  be  due  to  either  hypertropia 
or  myopia,  astigmatism  or  muscular  insufficiency  and  strabis- 
mus. These  should  be  properly  corrected  by  refraction 
measures  or  surgical  procedures.  When  uncorrected  they 
hinder  a  child's  progress  inasmuch  as  it  is  impossible  for  him  to 
follow  the  work  of  his  class  intelligently. 

AURAL  HYGIENE 

The  conditions  of  the  ear  of  greatest  importance  are  discharg- 
ing ears  and  defective  hearing.  Discharging  ears  should  receive 
suitable  medical  treatment,  while  those  having  defective  hearing 
should  receive  preferential  seating  in  class  rooms. 


HYGIENE    OF    CHILDHOOD  277 

HYGIENE  OF  THE  NOSE  AND  THROAT 

A  remarkable  and  close  correlation  exists  between  the  condi- 
tion of  a  child's  nose  and  throat  and  the  degree  of  intelligence 
it  manifests.  The  reasons  for  this  correlation  are  not  apparent. 
One  would  expect  to  find  such  a  correlation  to  exist  with  hearing 
and  vision  but  such  is  not  the  case  in  our  experience.  The 
conditions  of  greatest  importance  and  most  common  occurrence 
are  sore  throat,  hypertrophied  tonsils,  adenoids  and  nasal  ob- 
structions. These  require  suitable  medical  or  surgical  treat- 
ment for  alleviation. 

DENTAL  HYGIENE 

Faulty  conditions  of  the  nose  and  throat  may  profoundly 
influence  the  dentition.  Thus  adenoids  will  interfere  with  the 
development  of  the  jaw  and  produce  irregularities  of  the  teeth. 

Decay  or  caries  of  both  the  first  and  second  dentition  is  com- 
mon and  very  important.  The  fermentation  of  carbohydrate 
materials  in  food  particles  lodged  between  the  teeth  results  in 
the  production  of  lactic  acid,  which  is  a  solvent  for  dentine 
and  enamel.  Soft  carbohydrate  foods  rather  than  hard  tend 
to  lodge  in  these  situations.  Their  lodgment  is  favored  by  the 
buccal  mucous.  The  vigorous  mastication  of  hard  carbohy- 
drate foods  will  overcome  a  great  deal  of  this  difficulty. 

Pyorrhea  is  an  important  dental  defect  whose  cause  and 
prevention  is  unknown. 

Pus  pockets  about  the  roots  of  decaying  teeth  are  of  greater 
importance  than  their  small  size  and  localization  would  at  first 
indicate.  They  are  one  of  the  most  common  seats  of  focal 
infection  and  a  situation  from  which  infective  emboli  gain 
access  to  the  circulation  and  produce  disorders  elsewhere. 
Their  recognition  and  elimination  is  of  great  importance. 

It  is  advisable  to  make  inexpensive  repairs  to  the  early 
teeth,  as  their  premature  disappearance  may  unfavorably  affect 
the  second  dentition.  The  use  of  the  tooth  brush  should  be 
made  a  regular  habit. 

NUTRITIONAL  DEFICIENCIES 

Children  whose  state  of  nutrition  is  subnormal  show  a  dis- 
tinct lack  of  subcutaneous  fat,  they  are  under  weight,  thin, 
pale  and  have  pinched  faces.  The  condition  may  be  due  to  a 
lack  of  good  food,  or  to  insufficient  or  improper  food,  to  indiges- 


78 


PRACTICAL    PREVENTIVE    MEDICINE 


tion  or  improper  mastication.  Or  it  may  also  be  due  to 
a  lack  of  fresh  air  associated  with  overcrowding,  a  lack  of  rest 
or  overwork,  tuberculosis  or  diseases  of  the  liver  and  kidney. 

Each  of  these  possibilities  will  demand  investigation  and 
special  treatment  if  detected.  Where  due  to  insufficient  m  or 
improper  food  the  economic  status  of  the  parents  is  usually  the 
important  factor.  Some  means  of  charitable  relief  is  temporarily 
required.  One  solution  employed  is  to  provide  simple  lunches 
at  a  low  price  at  school. 

SCHOOL  SANITATION 

This  question  is  important,  inasmuch  as  the  schools  concern 
all  children.  Furthermore  the  close  association  between 
susceptible  children  at  school  makes  the  school  an  important 


Pig.  116. — School  with  insufficient  windows.  The  windows  are  not  large 
enough  to  provide  sufficient  light.  They  should  be  more  numerous  and  the 
window  panes  larger.      (Public  Health  Reports,  Sept.  n,  1914.) 

clearing  house  for  communicable  diseases.     The  many  import- 
ant features  in  school  sanitation  can  only  be  lightly  touched. 
(a)  Lighting. — A  general  and  safe  rule  is  that  lighting  space 
should  be  provided  in  each  room  in  the  proportion  of  one  square 


HYGIENE    OF   CHILDHOOD 


279 


foot  of  window  space  for  each  five  feet  of  floor  space.  In 
locating  the  seats  it  is  important  that  the  lighting  come  from 
the  left  and  that  none  be  permitted  to  shine  directly  into  the 
eyes  when  the  individual  is  properly  located  in  his  seat  (Fig. 
116,  118). 

(b)  Heating  and  Ventilation. — The  maintenance  of  the 
proper  mental  and  physical  efficiency  in  the  children  requires 
that  the  teachers  maintain  proper  conditions  of  temperature 


Pig.  117. — A  dangerous  school  privy.  Cover  to  seat  of  privy  and  door  to 
entrance  are  lacking,  thus  allowing  access  to  flies  and  animals.  Excreta  are 
deposited  upon  the  ground,  thus  bringing  about  soil  pollution.  Thirty-eight 
out  of  forty  children  in  this  school  were  found  to  be  infected  with  hookworm. 
The  percentage  of  hookworm  infection  in  the  county  in  which  this  school  is 
located  was  82.6.     (Public  Health  Reports,  Sept.  11,  1914.) 


and  humidity  in  the  class  rooms.     This  can  be  accomplished 
by  careful  supervision,  but  is  frequently  ignored. 

(c)  Blackboards  selected  for  recitation  or  demonstration 
purposes  should  be  so  situated  that  no  light  is  reflected  from 
their  surface  into  the  eyes  of  the  pupils.  These  should  have  a 
dull  black  surface. 

(d)  A  hygienically  satisfactory  supply  of  individual  drinking 


280 


PRACTICAL    PREVENTIVE    MEDICINE 


cups  should  be  available  or  drinking  fountains  should  be  used. 
Common  drinking  cups  should  not  be  tolerated. 

(e)  Adequate  toilet  facilities  with  separate  toilets  for  the  sexes 
are  necessary.  These  should  be  maintained  in  a  state  of  proper 
cleanliness  and  working  order.  Washing  facilities  and  indi- 
vidual towels  are  also  necessary.  Teachers  should  require  their 
use  by  children  who  come  to  school  with  dirty  faces  and  hands 
(Fig.  117). 

(/)  Proper  seating  of  the  children  with  regard  to  their 
stature  and  the  seats  available  is  necessary.  This  is  important 
from  the  standpoint  of  orthopedic  development. 


Pig.  118. — Front  of  classroom,  Cross  Roads  school.  Note  the  relation  of 
the  seating  and  black  boards  to  the  illumination.  (Bureau  Education,  Bull.  12, 
1914,  Plate  22.) 


(g)  The  method  employed  for  cleaning  class  rooms  should 
avoid  unnecessary  dust  production  and  should  preferably  be 
done  at  the  close  of  the  school  day.  Common  books  and 
pencils  tend  to  favor  the  distribution  of  infective  agents  and 
are  undesirable. 

(h)  Provision  should  be  made  for  one  or  more  periods  of 
physical  relaxation  during  the  school  day.  These  may  be 
devoted  to  drills,  games,  deep  breathing  exercises  or  a  recess. 

In  the  arrangement  of  the  curriculum  the  analytical  courses 
should  receive  first  place,  so  that  they  are  taken  while  the  mind 
is  fresh. 


HYGIENE    OF    CHILDHOOD  28l 


SCHOOL  INSPECTION 


The  medical  inspection  of  school  children  is  variously  under 
either  the  Board  of  Education  or  the  Board  of  Health,  or  in 
some  places  is  accomplished  jointly.  As  a  method  it  was 
especially  introduced  for  the  purpose  of  controlling  communi- 
cable diseases  by  the  regular  and  frequent  inspection  of  the 
children  to  detect  mild  cases,  carriers  and  convalescents,  and  to 
secure  their  exclusion  from  school  until  no  longer  infective. 
The  results  secured  in  this  direction  are  very  satisfactory.  It 
permits  the  rapid  checking  of  an  epidemic  without  serious  loss 
of  time  or  the  disorganization  of  the  school  work.  The  dis- 
missal or  closure  of  the  schools  for  an  indefinite  period  as  a 
measure  of  disease  control  has  little  to  commend  itself. 

A  more  recent  development  of  school  inspection  is  the  exten- 
sion of  its  scope  to  include  the  physical  defects  of  the  children 
and  make  available  provision  for  their  correction.  The  scope 
of  the  examination  made  is  most  commonly  limited  to  the  ears, 
eyes,  nose  and  throat,  teeth,  deformities,  nutrition  and  men- 
tality. As  a  rule  the  methods  of  examination  employed  are 
necessarily  not  as  detailed  as  those  in  ordinary  clinical  work, 
due  to  the  lack  of  time  and  assistance.  Their  purpose  is  to 
call  to  the  attention  of  the  parents  the  existence  of  defects  and 
to  emphasize  the  need  for  their  correction.  The  examina- 
tions should  be  made  by  a  competent  medical  man  and  follow 
up  work  at  the  children's  homes  is  best  accomplished  by  nurses. 
They  endeavor  to  enlist  the  cooperation  of  parents  so  that  the 
suggestions  offered  by  the  examiner  are  carried  out. 

REFERENCES 

Rosenau:  Preventive   Medicine   and   Hygiene.     3d,  Ed.,  pp.  1077-1098. 

Cornell:  Health  and  Medical  Inspection  of  School  Children. 

Gulick  and  Ayers:  Medical  Inspection  of  Schools. 

The  Health  of  School  Children.     Bull.  4,  1915  and  Bull.  50,  1915,   Bureau 

of  Education. 
Rural  School  Houses  and  Grounds.     Bull.  12,  1914,  Bureau  of  Education. 
Organized  Health  Work  in  Schools.     Bull.  44,  1913,     Bureau  of  Education. 
Schoolhouse  Sanitation.     Bull  21,  1915,  Bureau  of  Education. 
Rural  School  Sanitation.     Public  Health  Bull.  77,  Public  Health  Service. 


CHAPTER  XXXII 
AIR:  HEATING  AND  VENTILATION 

i.  Air  is  man's  immediate  environment  and  in  relation  to 
health  serves  two  important  functions.  The  oxygen  supply 
which  it  furnishes  may  justify  us  in  regarding  air  as  a  food, 
while  it  also  serves  an  important  function  in  the  regulation  of 
the  body's  temperature.     It  varies  in  the  following  directions: 

(a)  Chemical  Composition. — This  is  very  constant  out  of 
doors  all  over  the  world.  Variations  in  outdoor  air  are  slight 
and  are  only  found  over  small  areas.  On  the  other  hand,  the 
composition  of  indoor  air  is  very  variable,  due  to  the  constant 
admixture  with  expired  air.  It  is  a  simple  physical  mixture, 
the  approximate  proportions  being  shown  in  the  following 
table,  ignoring  rare  and  unusual  constituents. 


Outdoor  air 
per  cent,  by  vol. 


Expired  air, 
per  cent,  by  vol. 


Oxygen 

Nitrogen 

Carbon  dioxide 


20.81 

79-15 
0.03 


16.03 

79-55 
4-38 


(b)  Temperature  and  pressure  show  seasonal  and  altitudinal 
variations. 

(c)  The  possible  moisture  content  varies  directly  with  the 
temperature  and  pressure. 

(d)  Odors  are  variable ,  being  more  numerous  and  concentrated 
in  indoor  air. 

(e)  Air  is  subject  to  rapid  movement,  and  to  rapid  changes 
in  its  temperature,  pressure  and  moisture  content. 

Air  must  be  regarded  as  a  most  necessary  and  essential  food. 
In  this  respect  the  nitrogen  serves  as  a  harmless  diluent  for  the 
active  oxygen,  the  essential  constituent.  The  oxygen  effects 
the  combustion  of  the  food  eaten  and  stimulates  digestion  and 
metabolism. 

2.  By  good  air  is  meant  air  that  is  free  from  dust,  smoke  and 
odors,  of  moderate  coolness  and  humidity,  free  from  accumula- 

282 


air:  heating  and  ventilation  283 

tions  of  respiratory  products  and  body  excretions.     It  is  usually 
outside  air,  the  air  of  rural,  residential  or  unsettled  areas. 

3.  By  bad  or  injurious  air  is  meant  air  that  produces  discom- 
fort, which  is  chiefly  caused  by  heat  and  humidity,  and  odors 
in  the  air  of  inclosed  spaces.  Odors  are  the  chief  cause  of  dis- 
comfort and  their  intensity  is  increased  by  heat  and  humidity. 
Ordinarily  these  conditions  are  due  to  the  self  pollution  of  air 
about  a  sedentary  person,  the  aerial  blanket  about  the  individual 
being  saturated  with  his  excrement.  Odors  are  of  two  types, 
extraneous  and  intrinsic.  Extraneous  odors  include  those  due 
to  gas  works,  bone  boiling  plants,  rendering  plants,  slaughter 
houses,  stables  and  meat  markets.  Intrinsic  odors  arise  from 
the  sudoriferous  glands,  from  bad  teeth,  bad  breath,  gases  from 
the  stomach  and  rectum,  or  urine  decomposing  on  the  clothing. 
These  are  not  detectable  on  chemical  analysis.  The  necessary 
temperature  and  humidity  to  accentuate  odors  may  be  produced 
by  the  body,  the  heat  being  furnished  by  direct  radiation  and 
the  humidity  from  the  expired  air  and  perspiration. 

4.  In  addition  air  may  contain  certain  various  undesirable 
or  injurious  substances  not  due  to  respiration.  Thus  there  may 
be  present  dust  from  various  sources  (metals,  stone,  wood,  soil, 
manure,  cotton,  wool,  etc.)  soot  and  smoke.  The  latter  are 
products  of  combustion  and  add  sulphurous  acid  and  carbon 
dioxide.  The  air  of  industrial  establishments  may  be  contami- 
nated by  dust  and  fumes  of  varying  kinds.  These  have  already 
been  considered. 

5.  Effect  of  Temperature  and  Humidity. — The  human  body 
is  readily  adaptable  to  temperatures  from  o  degrees  F.  to  80. 
degrees  F.  Temperatures  above  or  below  these  limits  produce 
discomfort.  Discomfort  from  both  of  these  factors  arises  from 
the  disturbances  they  produce  in  the  heat  regulating  devices 
of  the  body.  The  bodily  activities  produce  an  excess  of  heat 
which  must  be  lost  or  heatstroke  will  result.  Heat  is  lost  by 
(1)  heat  transfer  which  is  affected  by  radiation,  conduction,  and 
convection,  and  by  (2)  evaporation  (perspiration)  whose 
amount  diminishes  as  the  surrounding  humidity  and  tem- 
perature rise.  Without  free  perspiration  the  temperature  of 
the  body  rises  if  the  external  temperature  goes  above  70  degrees 
F.  As  long  as  free  evaporation  persists  the  heat  production 
and  heat  loss  are  balanced.  When  humidity  is  high  evapora- 
tion is  lessened  and  the  balance  is  maintained  by  an  increased 
flow  of  blood  to  the  skin  and  consequently  an  increase  in  the 
loss  of  heat  by  transfer.     Humidity  affects  the  heat  output 


284  PRACTICAL   PREVENTIVE   MEDICINE 

by  (1)  increasing  the  conductivity  of  the  atmosphere  for  neat 
^thus  cold  moist  air  is  chilling)  and  (2)  interferes  with  the 
evaporation  of  perspiration  (thus  warm  moist  air  is  ennerva- 
ting).  Around  a  temperature  of  68  degrees  F.  humidity  exer- 
cises a  minimum  influence.  Humidity  should  not  exceed  70 
degrees  F.  as  measured  on  a  wet  bulb  thermometer.  Tempera- 
ture and  humidity  are  perhaps  the  most  important  factors  in 
ventilation. 

Warm  moist  air  is  not  directly  injurious.  Chilling  on 
leaving  such  an  atmosphere  may  occur.  When  air  about  80 
degrees  F.  becomes  saturated,  evaporation  no  longer  com- 
pensates for  the  decreased  radiation  and  heat  stroke  may  follow 
the  rise  in  body  temperature  which  follows.  The  effect  of  this 
temperature  is  diminished  by  light  clothing. 

Cold  damp  air  is  injurious  to  poorly  clad,  improperly  fed 
persons  either  in  infancy  or  old  age,  or  to  those  having  kidney 
disease,  rheumatism,  disorders  of  metabolism  or  affections  of  the 
respiratory  passages.  Its  effect  is  diminished  by  proper  cloth- 
ing, exercise  and  an  increased  diet. 

Warm  dry  air  produces  the  most  comfortable  sensations  and 
is  stimulating.  Hot  dry  air  causes  an  excessive  loss  of  moisture 
and  favors  irritation  and  infection  of  the  respiratory  mucosa. 

6.  The  relation  of  man  to  air  varies  in  different  climates. 
Thus  in  the  tropics  he  needs  no  fire  for  warmth,  no  clothing 
except  for  modesty  and  no  work  to  keep  warm.  The  heating 
and  ventilation  of  the  home  is  of  little  consequence,  since  there 
is  little  home  life.  On  the  other  hand  in  the  arctics  fires  are 
needed  for  warmth,  while  fuel  is  scarce,  and  heavy  clothing  is 
required  to  conserve  the  body  heat.  As  a  consequence  both 
heating  and  ventilation  of  the  home  is  required.  The  temperate 
climate  furnishes  both  of  the  above  extremes  during  its  seasonal 
variations. 

7.  Carbon  Dioxid. — Carbon  dioxid  was  formerly  considered 
injurious  and  also  an  index  of  the  wholesomeness  of  air.  It  is 
not  irritating  or  poisonous.  Its  percentage  cannot  be  taken 
as  a  guide  to  the  fitness  of  air  for  breathing,  and  we  can  only 
employ  its  determination  as  a  guide  to  the  amount  of  rebreath- 
ing  (vitiation)  which  has  taken  place,  while  it  cannot  be 
substituted  for  the  more  important  determinations  of  tempera- 
ture, humidity,  and  motion.  Ordinarily  it  never  accumulates 
in  quantities  sufficient  to  cause  injury.  It  is  tolerated  in 
quantities  up  to  .10  to  .13  per  cent.;  from  2  to  3  per  cent,  prod- 
uce  increased   respiration,    from    7    to   8    per    cent,    produce 


air:  heating  and  ventilation  285 

distressing  dyspnoea  and  10  to  11  per  cent,  produce  headache, 
nausea  and  chilliness.  Suffocation  will  occur  in  an  atmosphere 
of  30  per  cent. 

8.  Heating. — The  body  must  be  regarded  as  a  furnace,  a 
radiator,  a  thermostat  and  a  humidifier.  It  not  infrequently 
produces  more  heat  than  is  needed,  whereupon  no  external 
heat  is  required.  Less  artificial  heat  is  required  by  young 
persons,  women,  and  by  all  persons  when  exercising.  In 
sedentary  life  and  old  age  the  heat  loss  is  in  excess  of  heat 
production  and  then  one  needs  to  surround  the  body  with  an 
air  blanket  of  a  temperature  that  in  winter  will  supply  heat  to 
the  body.  The  young  and  active  require  an  air  blanket  that 
will  absorb  heat.  Thus  a  study  should  be  kept  warm  and  a 
gymnasium  cool.  Next  to  the  body  is  a  partial  blanket  of  air 
enmeshed  in  the  hair  and  clothing,  which  serves  as  an  insulator. 
This  is  present  except  when  a  person  is  exposed  to  winds. 
Thinly  clad  persons,  or  persons  who  are  poorly  nourished,  tend 
to  overheat  their  dwellings,  due  to  insufficient  bodily  heat 
production. 

Artificial  heating  as  a  practice  antedates  ventilation.  At 
present,  especially  in  large  buildings,  the  two  are  frequently 
combined  but  it  is  a  difficult  master  to  secure  satisfactory  results. 
Artificial  heating  is  usually  with  dry  air.  The  capacity  of  win- 
ter air  for  moisture  is  greatly  increased  after  heating,  for  when 
cold,  even  if  saturated,  it  contains  relatively  little  moisture. 
Artificial  humidification  is  therefore  required. 

Artificially  heat  is  supplied  by  various  means;  (1)  by  open 
fire  places,  (2)  by  stoves,  (3)  by  hot  air  furnaces,  (4)  by  the 
enclosed  circulation  of  steam  and  hot  water,  (5)  by  gas  and  oil 
stoves  and  braziers  and  (6)  by  electrical  heaters.  The  first 
two  of  these  methods  usually  improve  the  ventilation  of  the 
heated  spaces,  since  the  source  of  the  heat  is  an  open  flame 
within  the  room,  which  requires  a  current  of  air  for  its  active 
burning,  and  in  order  to  avoid  the  smoke  the  gases  are 
conveyed  outside.  These  currents  result  in  fresh  air  being 
drawn  into  the  room  from  out  of  doors,  Gas  and  oil  stoves 
vitiate  the  air,  since  their  gases  of  combustion  are  discharged 
into  the  room.  If  maintained  in  a  small  room  actual  danger 
may  arise,  due  to  high  concentrations  of  carbon  monoxid 
accumulating  near  the  floor. 

9.  Ventilation. — The  purpose  of  ventilation  is  to  maintain 
the  air  of  enclosed  spaces  in  a  condition  that  will  result  in  the 
comfort  of  those  using  it.     It  does  not  necessarily  imply  the 


286  PRACTICAL    PREVENTIVE    MEDICINE 

displacement  of  air,  but  should  provide  for  its  motion.  It  is 
impossible  to  make  estimates  of  the  proper  allowance  or  condi- 
tion of  air  by  any  cubic  foot  per  capita  allowance.  If  the  air 
in  an  enclosed  space  is  maintained  at  not  over  68  degrees  F., 
without  excess  humidity  and  in  slight  motion  a  person  will  be 
confortable  and  the  air  can  be  rebreathed  many  times  without 
discomfort. 

In  a  consideration  of  the  air  in  enclosed  spaces  attention 
should  be  called  to  both  the  breathing  zone  and  the  breathing- 
cone.  The  breathing  zone  in  a  room  includes  the  air  lying 
within  those  limits  from  which  a  person  draws  air  while  either 
sitting  or  standing.  If  the  air  is  stagnant  and  contains  much 
smoke  its  limits  will  be  visibly  defined.  The  breathing  cone 
consists  of  a  more  or  less  conical  zone  of  rebreathed  air  surround- 
ing a  sedentary  person,  whose  apex  is  at  his  nostrils.  The 
circulation  of  the  air  of  an  enclosed  space  breaks  up  these  local 
concentrations  of  respired  air. 

Ventilation  is  either  natural  or  artificial.  Natural  ventilation 
is  due  to  either:  (a)  gravity  and  diffusion,  or  (b)  perflation  and 
aspiration.  The  former  represents  the  diffusion  of  air  into 
a  room  through  porous  walls  and  the  spaces  around  doors 
and  windows.  The  warm  air  escapes  and  is  replaced  by  cool 
air.  It  is  important  in  the  ventilation  of  small  rooms.  Perfla- 
tion is  the  ventilation  secured  by  the  removal  of  obstacles  to 
wind  pressure,  such  as  that  accomplished  by  the  opening  of 
windows.  The  effect  of  aspiration  is  shown  by  the  air  currents 
in  flues  and  chimneys.  It  is  assisted  by  the  provision  of 
movable  chimney  cowls  which  turn  the  vent  away  from  the 
wind. 

Mechanical  ventilation  is  the  propulsion  or  extraction  of  air 
by  means  of  fans  or  blowers  whose  operation  is  continuous. 
It  is  of  two  types:  (a)  the  plenum  system  and  (b)  the  vacuum 
system.  In  the  first  the  air  is  forced  in  by  a  blower,  having  an 
intake  at  the  ground  level.  In  the  second  the  air  is  withdrawn 
by  an  exhaust  fan  and  the  intake  is  secured  by  the  seepage  of 
air  through  walls  and  around  windows.  It  gives  rise  to  drafts. 
The  plenum  system  is  used  in  connection  with  heating  systems 
and  automatic  thermo-regulation.  As  a  rule  it  does  not  work 
satisfactorily  if  influenced  by  factors  of  natural  ventilation. 
The  air  at  the  intake  is  washed  to  remove  dust  and  also  to  humid- 
ify it,  warmed  by  passage  over  steam  coils  and  distributed 
through  ducts.  The  best  diffusion  is  secured  where  the  discharge 
of  warm  air  is  near  the  ceiling,  and  the  outlet  is  on  the  same  wall 


air:  heating  and  ventilation  287 

near  the  floor.  Both  systems  so  far  are  only  practicable  for 
large  buildings. 

10.  The   Management  of  Halls  and  Large  Rooms. — It  is 

possible  to  so  manage  these  enclosures  during  winter  months 
that  a  large  audience  will  be  comfortable  and  alert  during  the 
period  of  their  congregation.  Good  results  will  be  secured  if 
the  hall  is  filled  with  fresh  air  at  about  60  degrees  before  the 
audience  congregates.  The  intakes  are  then  closed.  The 
audience  should  be  watched  closely  and  if  a  slight  general 
coughing  starts  or  if  a  scattering  of  women  clear  their  throats, 
a  little  heat  should  be  turned  on. 

In  hot  weather  every  endeavor  to  secure  the  beneficial  effects 
of  perflation  by  removing  all  obstacles  to  wind  pressure  should 
be  made.  In  enclosed  halls  and  theatres  where  such  is  not 
possible  the  installation  of  artificial  cooling  systems  based  upon 
the  circulation  of  cold  brine,  is  of  material  value. 

REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene.     3rd.   Ed.,   pp.   661-776. 

Report  of  the  Chicago  Commission  on  Ventilation.     1914. 

Barometers   and   the   measurement    of    atmospheric    pressure.     Circ.    F. 

Instrument  Division  U.  S.  Weather  Bureau. 
Psychrometric  Tables  for  Obtaining  the  Vapor  Pressure,  Relative  Humidity 

and  Temperature  of  the  dew  point.     U.  S.  Weather  Bureau. 


CHAPTER  XXXIII 
CERTAIN  ASPECTS  OF  PERSONAL  HYGIENE 

Many  references  to  the  care  of  the  body  in  order  to  promote 
its  proper  functioning  have  already  been  made  on  previous 
pages  in  connection  with  some  phase  of  preventive  medicine. 
Here  we  shall  briefly  consider  topics  not  heretofore  mentioned. 

EXERCISE 

By  exercise  we  mean  the  functional  activity  of  the  body, 
particularly  muscular  activity.  The  individual  is  in  relation 
to  the  outer  world  in  two  respects,  (i)  by  the  sensations  re- 
ceived, and  (2)  by  muscular  efforts  which  produce  environ- 
mental changes.  The  muscular  tissues  make  up  most  of  the 
body  bulk  and  are  the  seat  of  most  of  the  metabolism.  The 
body  is  so  constructed  as  to  be  adapted  to  muscular  exertion 
which  is  necessary  for  the  maintenance  of  the  body  in  normal 
condition. 

INFLUENCE  OF  EXERCISE 

(a)  On  Metabolism. — Exercise  burns  up  carbonaceous  ma- 
terial but  does  not  increase  the  nitrogen  consumption.  The 
chief  carbonaceous  fuel  is  dextrose,  which  is  stored  up  as  a 
reserve  fuel  in  the  liver  in  the  form  of  glycogen.  During  exercise 
the  dextrose  is  oxidized  to  lactic  acid,  and  if  sufficient  oxygen  is 
present,  to  carbon  dioxid.  Not  only  does  exercise  bring  into 
activity  the  muscular  tissues,  but  all  the  other  organs  of  the 
body  as  well.  These  activities  involve  both  anabolism  and  kata- 
bolism.  If  exercise  is  so  great  that  anabolism  cannot  build  up 
what  katabolism  destroys,  the  individual  loses  weight. 

(b)  On  the  Flow  of  Blood  and  Lymph. — This  is  at  a  maximum 
during  work,  due  to  an  automatic  dilation  of  the  bloodvessels 
in  the  muscles.  This  is  assisted  by  the  pumping  effect  which 
the  rhythmic  heart  action  has  on  the  veins. 

(c)  On  the  Heart. — The  heart  readily  adapts  itself  to  exer- 
cise. This  is  accomplished  by  the  metabolites,  and  by  cerebral 
impulses  to  the  skeletal  muscles  which  inhibit  the  vagus  tone. 


CERTAIN   ASPECTS    OF    PERSONAL    HYGIENE  289 

(d)  On  the  Arterial  Pressure. — This  is  increased,  due  to  a 
constriction  of  the  splanchnic  vessels  to  compensate  for  the 
dilation  of  the  cutaneous  and  mucular  vessels,  thus  increasing 
the  pressure.  The  amount  of  the  pressure  varies  with  the 
exercise.  Its  function  is  probably  to  supply  a  head  of  pressure, 
so  that  if  there  is  a  demand  on  one  part  of  the  body  the  blood 
may  flow  there  without  leaving  the  rest  unsupplied.  A  blood 
pressure  of  about  90  mm.  of  mercury  will  produce  a  decreased 
muscular  efficiency.  In  a  healthy  person  exercise  will  im- 
mediately cause  the  pressure  to  rise,  it  then  soon  falls  some- 
what to  a  constant  level  which  is  maintained  during  the  period 
of  exercise,  then  falls  below  normal  with  rest  and  gradually  is 
restored. 

(e)  On  Respiration. — The  carbon  dioxid  produced  causes  a 
deepening  and  quickening  of  respiration. 

(/)  On  Heat  Production  and  Regulation. — The  increased 
fuel  consumption  of  exercise  results  in  the  production  of  con- 
siderable heat.  This  requires  the  action  of  the  heat  regulating 
mechanism,  so  that  the  body  temperature  will  not  ascend  too 
high.  Exercise  may  cause  a  rise  of  as  much  as  four  degrees 
Fahrenheit  above  normal. 

(g)  On  Perspiration. — The  stimulation  of  the  sweat  glands 
causes  an  increase  in  the  amount  of  perspiration.  By  this 
means  water  and  salts,  chiefly  the  former,  are  eliminated. 

(h)  On  Digestive  Processes. — Digestion  and  absorption  go 
on  equally  well  with  rest  and  muscular  exercise.  On  the  other 
hand,  exercise  increases  the  appetite  and  decreases  constipation 
by  stimulating  the  activity  of  the  colon. 

(i)  On  Slumber. — This  is  promoted  by  the  development 
of  a  healthy  fatigue. 

(j)  On  Muscular  Tissues. — Those  tissues  not  involved  in 
exercise  undergo  an  atrophy.  On  the  other  hand,  exercise 
increases  the  size  of  muscle  fibers  but  not  their  number.  If 
the  muscular  fibers  are  overworked,  permanent  shortening 
results  and  the  individual  is  said  to  be  "muscle  bound." 

EFFECTS  OF  EXERCISE 

Exercise  produces  the  following  effects  which  may  be  regarded 
as  favorable,  namely,  an  increase  in  the  size  of  the  exercised 
muscles,  increased  anabolism  and  a  healthy  fatigue.  The 
following  conditions  that  can  result  from  exercise  may  be 
considered  injurious,  namely,  pain  from  muscle  soreness,  muscle 
19 


290  PRACTICAL   PREVENTIVE    MEDICINE 

binding,  production  of  inguinal  and  femoral  hernias,  and 
probably  it  also  serves  as  a  factor  in  the  production  of  arterio- 
sclerosis. 

Exercise  should  never  be  excessive  or  potentially  injurious. 
Of  this  the  individual  is  the  best  judge.  It  should  be  avoided 
in  conditions  of  great  fatigue  and  in  cardiac,  vascular  and  pul- 
monary disease  it  should  be  employed  with  great  caution. 
Interest  in  exercise  is  desirable.  It  is  for  this  reason  that 
locomotory  games  are  hygienically  valuable. 

FATIGUE 

This  is  the  weariness  resulting  from  muscular  or  functional 
activity.  The  vegetative  activities  of  the  body,  such  as  the 
nutritive  functions,  reproductive  activity,  smooth  muscle 
action,  glandular  activity,  etc.,  are  not  subject  to  will  power. 
These  activities  set  their  own  pace  and  therefore  are  not 
subject  to  fatigue.  On  the  other  hand,  the  animal  activities, 
including  work  and  locomotion,  are  subject  to  the  will  and  stimu- 
lation and  may  thus  be  set  to  limits  beyond  the  individual's 
own  welfare.  The  receptors,  neurones  and  muscles  are  the  sites 
of  fatigue. 

(a)  Receptor  fatigue  is  fatigue  of  the  end  organs.  We  may 
particularly  distinguish  fatigue  of  the  olfactory,  auditory  and 
optic  end  organs.  Some  odors  affect  the  ability  to  distinguish 
similar  or  other  odors,  which  must  be  considered  a  manifesta- 
tion of  fatigue.  Auditory  fatigue  only  affects  the  ability  to  hear 
sounds  in  higher  register.  Optic  fatigue  is  manifested  by  a 
reduced  visional  acuity. 

(b)  Neuron  fatigue  occurs  centrally,  the  axone  being  con- 
sidered indefatigueable.  Morphologic  changes  in  the  nerve 
cells  and  nucleus  with  a  chromatolysis  are  observable,  and 
physiologic  changes,  as  shown  by  a  rise  in  the  threshold  value 
between  neurons,  are  seen  in  the  spinal  reflexes. 

(c)  Muscle  fatigue  may  reside  in  the  end  plate  or  muscle 
fiber.  The  end  plate  may  be  fatigued  while  the  muscle  is 
still  capable  of  contracting.  The  muscle  contraction  varies 
with  constant  or  variable  loads.  With  a  constant  load  the  con- 
tractions will  finally  cease,  while  with  a  variable  load  they  will 
go  on  indefinitely.  The  rate  at  which  they  contract  is  as  im- 
portant as  the  load  in  the  production  of  fatigue.  The  fatigued 
muscle  is  less  irritable  to  stimulation,  but  increased  stimulation 
will  produce  an  increase  in  the  height  of  contraction.     The 


CERTAIN    ASPECTS    OF    PERSONAL    HYGIENE 


291 


reaction  of  the  muscular  protoplasm  changes  to  acid  from  neu- 
tral or  alkaline,  due  to  the  formation  of  sarcolactic  acid  and 
monopotassium  phosphate.  The  acid  is  dissipated  by  outward 
diffusion,  or  oxidation  to  carbon  dioxid.  As  a  consequence 
lactates  and  lactic  acid  may  appear  in  the  blood  and  urine 
following  fatigue.  Muscular  fatigue  is  due  to  the  accumulation 
of  these  waste  products  in  either  the  muscles  or  the  blood.  If 
in  the  muscle  their  accumulation  may  be  due  to  the  failure  of 
the  blood  stream  to  remove  them.  The  massage  of  a  fatigued 
muscle  assists  in  the  removal  of  the  fatigue  products  by  the 
circulation.  Recovery  is  also  hastened  by  oxygen.  The  ac- 
cumulation of  fatigue  products  in  the  blood  affects  muscles 
other  than  the  ones  involved  in  the  exercise,  thus  local  fatigue 
becomes  general. 

Fatigue  is  temporarily  overcome  by  excitement.  In  both 
laziness  and  fatigue  work  is  done  with  a  sense  of  effort,  probably 
due  to  a  rise  in  the  threshold  value,  and  to  the  accumulated 
waste  products.  When  the  threshold  value  of  the  neuro-mus- 
cular  junction  rises  as  fatigue  progresses,  the  innervation 
spreads  to  other  groups  of  muscles  in  order  that  the  work  may 
be  accomplished.  This  brings  more  nerves  and  muscles  into 
play  and  increases  the  amount  of  metabolites  in  the  circulation 
and  hence  produces  a  greater  sense  of  fatigue.  As  fatigue 
appears  the  movements  of  the  muscles  become  less  exact  and 
their  co-ordination  is  less  perfect.  This  has  a  bearing  upon 
industrial  accidents  as  shown  in  the  following  figures. 

TABLE  XI 

Industrial  Accidents  in  the  German  Empire,  1887 


Morning 

Evening 

Hours 

No.  of  accidents 

Hours 

No.  of  accidents 

6-7 

445 

1 2- 1 

587 

7-8 

794 

1-2 

745 

8-9 

8i5 

2-3 

i,o53 

9-10 

1,069 

3-4 

1,243 

io-ii 

i,594 

4-5 

1,178 

11— 12 

1,59° 

5-6 

1,306 

Fatigue  also  reduces  the  rapidity  and  accuracy  of  action  and 
also  diminishes  the  extent  of  mental  control.  There  is  also 
an    increase    in    irritability    and    irascibility.     Garrulity    and 


292  PRACTICAL   PREVENTIVE    MEDICINE 

uncontrollable  laughter  may  appear  to  an  extent  which  is  almost 
hysterical.  Normally  fatigue  is  a  protective  sensation  indi- 
cating the  need  of  rest.  It  reduces  the  general  sensibility 
of  the  body. 

Nervous  fatigue,  on  the  other  hand,  involves  the  activities 
of  the  central  nervous  system  itself.  It  is  of  importance  be- 
cause the  changing  racial  habits  of  our  times  require  constant 
alertness,  necessitating  quick  adjustments  rather  than  much 
muscular  work. 

REST  OR  RELAXATION 

Rest  permits  the  accumulations  of  waste  to  be  excreted 
and  the  destroyed  material  to  be  replaced.  The  greatest 
rest  is  achieved  during  sleep.  Sleep  is  favored  by  warmth  and 
quiet,  especially  toward  the  senses  of  sight  and  sound,  "com- 
fortableness," and  complete  relaxation.  It  is  also  aided  by  a 
neutral  bath  or  any  dull  monotonous  sound.  Brain  workers 
need  less  sleep  than  laborers.  Eight  hours  is  the  average 
duration  of  sleep  normally. 

A  change  of  work  also  permits  of  rest,  especially  with  mental 
work.  Long  periods  of  mental  work  are  unfavorable  to  mus- 
cular work  and  vice  versa.  If  either  are  in  excess  one  had  better 
rest  than  change  from  one  to  the  other. 

BATHING 

The  sebaceous  and  perspiratory  secretions  of  the  skin  require 
more  or  less  frequent  removal.  This  is  best  accomplished  by 
bathing  or  washing  the  body  in  water.  Those  localities  where 
the  sweat  is  most  likely  to  be  poured  out  should  be  bathed 
daily  in  order  to  prevent  accumulations  which  produce  un- 
pleasant odors.  Furthermore  a  clean  skin  is  less  likely  to  be 
diseased  than  a  dirty  one.  Bathing  reduces  the  likelihood  that 
body  vermin  might  be  able  to  establish  a  foothold.  Too 
strongly  alkaline  a  soap  should  not  be  used  or  ,the  skin  will 
become  dry.  The  oil  removed  should  be  replaced  by  inunctions 
with  lanolin  or  cocoa  butter.  Lastly  the  bathing  of  the  hands 
and  face,  especially  before  eating  and  the  avoidance  of  intro- 
ducing the  fingers  into  the  mouth  until  after  they  have  been 
washed,  is  an  important  safeguard  against  the  introduction  of 
infective  agents  by  contact. 

The  250,000  cold  spots  and  the  300,000  warm  spots  are 
stimulated  by  temperatures  differing  from  that  of  the  body. 


CERTAIN    ASPECTS    OF    PERSONAL    HYGIENE  293 

Thus  in  bathing  the  skin  is  stimulated  by  thousands  of  afferent 
stimuli.  Baths  are  designated  according  to  their  temperature 
as  follows: 

Cold 65  degrees  F. 

Cool 65-80  degrees  F. 

Tepid 80-90  degrees  F. 

Warm 90-98  degrees  F. 

Hot 98  or  over. 

Cold  baths  stimulate  and  are  employed  for  that  purpose. 
A  reaction  is  induced  by  an  exposure  to  cold  of  from  ten  to 
thirty  seconds  duration.  The  immediate  effect  consists  in  the 
dilation  of  the  internal  blood-vessels,  a  contraction  of  the 
cutaneous  vessels,  "goose  flesh,"  cutaneous  pallor,  a  sensation 
of  cold,  shivering,  an  increased  heart  rate  which  soon  decreases, 
with  a  decreased  respiration.  The  secondary  effect  is  known 
as  the  reaction.  It  is  manifested  by  a  slow  and  deep  respiration, 
a  reddening  of  the  skin  as  the  blood  returns  to  the  surface, 
accompanied  by  a  feeling  of  warmth,  perspiration  and  a  sense 
of  exhilaration.  A  warm  body  and  skin  before  the  bath  tends 
to  favor  the  reaction.  The  temperature  of  the  bath  should  be 
as  cold  as  may  be  tolerated.  Cold  baths  should  not  be  em- 
ployed in  infancy,  old  age,  exhaustion,  or  fatigue. 

Hot  baths  are  better  for  purposes  of  cleanliness  after  muscular 
work  resulting  in  soreness.  They  are  useful  when  the  irritabil- 
ity of  the  person  is  increased  or  when  one  has  insomnia.  Very 
hot  baths  of  ioo  degrees  F.  produce  a  reflex  resembling  the 
effect  of  cold  baths.  The  enervating  effect  is  manifested 
by  a  lower  irritability  or  indisposition  for  muscular  work.  It 
may  be  overcome  by  a  cold  dash. 

A  bath  at  the  body  temperature  produces  very  slight  effect. 
It  has  a  calming  effect  and  is  used  in  the  treatment  of  the  insane. 
It  is  best  for  weak  individuals  or  where  cleanliness  is  the  object 
of  the  bath. 

Prolonged  bathing  may  produce  the  following  ill  effects, 
namely,  nausea,  faintness,  giddiness,  weakness,  dyspnoea, 
and  a  subnormal  temperature. 

CLOTHING 

Clothing  is  worn  both  for  purposes  of  modesty  and  to  main- 
tain a  constant  body  temperature.  In  this  connection  it  must 
be  borne  in  mind  that  the  skin  is  the  most  important  organ  in 
temperature  regulation.  Clothing  aids  in  protection  from  the 
effects  of  a  lowered  temperature  by  holding  warm  air  enmeshed 


2Q4  PRACTICAL    PREVENTIVE    MEDICINE 

(insulation),  so  that  the  body  lives  in  a  temperate  climate, 
and  also  by  influencing  conduction,  convection  and  evaporation. 

Heat  losses  by  conduction  are  favored  by  clothing  made  of 
plant  fibers,  since  these  conduct  heat  outwards  better,  although 
heat  losses  by  this  means  are  relatively  slight.  Furthermore 
the  extent  of  the  loss  is  reduced  by  the  air  enmeshed  in  the 
fabric,  which  factor  is  however  greater  in  fabrics  made  from 
animal  fibers,  since  their  elasticity  is  less  affected  by  laundering. 

Heat  losses  by  conduction  are  favored  by  anything  which 
permits  the  warm  air  close  to  the  body  to  be  blown  away.  The 
degree  to  which  this  occurs  is  influenced  by  the  porosity  of  the 
clothing.  Of  fabrics,  flannel  is  the  most  porous  and  silk  the 
least.  Leather,  paper  and  rubber  prevent  heat  losses  by  this 
means. 

If  the  spaces  in  the  fabric  be  filled  with  water,  the  losses  by 
evaporation  as  well  as  by  conduction  are  increased.  Thus  wet 
clothes  may  chill  the  skin,  and  the  cessation  of  exercise  while 
the  clothing  is  wet  may  be  dangerous.  Wool  has  the  greatest 
hygroscopic  power  of  all  fabrics,  so  that  water  evaporates 
slowly  from  it.  An  ideal  fabric  would  permit  sweat  to  evapo- 
rate when  poured  out  and  would  not  stay  wet  when  sweating 
ceases,  or  do  away  with  the  enmeshed  air  when  wet. 

The  fabrics  which  make  the  most  suitable  clothing  to  be 
worn  next  to  the  skin  in  summer  and  warm  climates  are  cotton 
or  close  meshed  linen.  For  cold  climates  and  for  individuals 
who  get  little  exercise  wool  is  best.  There  are  differences  of 
opinion  concerning  those  best  adapted  to  individuals  likely  to 
get  wet.  Some  advocate  wool,  for  it  absorbs  sweat  and  still 
enmeshes  air.  Others  object  to  it  as  it  does  not  permit  quick 
heat  losses  and  dries  slowly.  Others  favor  cotton,  especially 
coarse  meshed  fabrics,  for  permitting  a  quick  heat  loss. 
Objections  raised  to  it  are  the  fact  that  it  wets  through  rapidly 
and  no  air  spaces  are  left,  while  the  heat  losses  maybe  too  rapid. 

Outer  clothing  in  the  summer  is  worn  chiefly  for  appearances. 
It  should  be  as  permeable  as  possible  and  for  this  purpose  cotton 
or  linen  are  best.  In  winter  woolen  is  the  fabric  of  choice. 
If  one  is  in  the  wind,  impermeable  goods  should  be  selected.  If 
a  person  lives  mainly  indoors  in  the  winter  the  outer  clothing 
need  be  the  only  change  of  adaptation.  If  one  exercises  in  the 
cold  do  not  make  any  change  except  to  leave  off  the  outer 
clothing  while  exercising. 

The  color  of  clothing  has  no  effect  on  the  radiation  of  the  heat. 
Those  colors  which  reflect  the  most  heat  absorb  the  least. 


CHAPTER  XXXIV 
DOMESTIC  SANITATION 

The  sanitation  of  the  home  does  not  present  any  features 
that  distinguish  it  from  other  problems  of  sanitation.  ^  Rather 
it  is  the  application  of  principles  we  have  discussed  in  detail 
elsewhere  in  their  particular  relationship  to  the  home.  Therefore 
we  cannot  expect  to  find  that  very  much  new  material  will  be 
presented  at  this  time. 

LOCATION 

Other  things  being  equal,  an  elevated  well  drained  situation 
is  preferable  for  the  location  of  a  dwelling.  The  importance  of 
this  factor  is  probably  not  so  great  as  was  considered  at  one  time, 
but  nevertheless  should  not  be  ignored.  Poorly  drained  loca- 
tions will  permit  accumulations  of  water  close  to  dwellings 
and  hence  result  in  mosquito  breeding,  the  contamination  of  wells 
is  made  more  likely  and  in  an  effort  to  fill  or  raise  the  ground 
level,  poor  filling  material  is  apt  to  be  used,  so  that  rat  harbour- 
age on  the  premises  is  favored. 

CONSTRUCTION 

The  various  materials  from  which  dwellings  are  constructed 
are  about  equally  valuable  from  a  hygienic  standpoint. _  In 
other  words  it  is  possible  to  construct  dwellings  of  equal  hygienic 
value  from  wood,  brick,  stone,  concrete,  or  any  other  material. 
An  important  point  in  construction,  regardless  of  the  materials 
used,  is  to  make  the  dwelling  rodent  proof.  This  is  largely  a 
matter  of  neat  and  careful  workmenship,  especially  in  the  case 
of  frame  dwellings  in  which  special  precautions  must  be  ob- 
served. The  building  must  fit  its  foundation  closely  and  all 
spaces  between  the  floors  and  walls  sealed  tightly  with  brick 
or  cement  through  which  rodents  cannot  gnaw.  This  can  t>e 
done  by  filling  the  spaces  between  the  studdings  above  the  sills 
for  a  distance  of  six  or  eight  inches  with  mortar  or  bricks.  Like- 
wise the  openings  in  the  basement  floors,  and  walls,  as  well  as 
the  basement  ceilings  through  which  pass  conduits,  drain  pipes, 

295 


296  PRACTICAL    PREVENTIVE    MEDICINE 

water,  and  gas  pipes  etc.,  should  be  tightly  sealed  with  cement 
or  flashed  with  tin.  Knot  holes  should  be  tightly  sealed  with 
sheet  tin.  The  provision  of  smooth,  tight  floors  is  likewise 
an  important  matter  in  promoting  the  future  cleanliness  of 
the  dwelling,  since  less  labor  i&  required  in  keeping  such  floors 
clean  than  those  which  are  rough  and  have  large  cracks. 

LIGHTING 

Every  dwelling  should  be  so  situated  that  at  some  time  of  the 
day  each  of  the  sides  will  receive  the  sun's  rays.  Little  can  be 
said  in  favor  of  the  type  of  dwelling  construction  common  in 
large  cities,  where  for  blocks  dwellings  or  tenements  occupy 
the  entire  lot  space,  only  presenting  free  wall  space  at  the  front 
and  rear.  The  interior  rooms  of  such  dwellings  receive  very 
little  natural  illumination.  The  type  of  construction  we  earlier 
recommended  is  best,  for  first  it  permits  full  advantage  to  be 
taken  of  the  brightly  diffused  sunlight  for  the  illumination  of 
the  dwelling's  interior  during  the  day,  and  second,  each  room 
for  some  period  of  the  day  will  have  a  greater  or  less  amount  of 
direct  sunlight  gaining  entrance,  and  thus  be  benefited  by  its 
germicidal  activity.  Furthermore  as  we  shall  presently  see,  such 
construction  enables  the  fullest  advantage  to  be  taken  of  natural 
ventilation. 

Narrow  streets  and  high  dwellings,  particularly  those  of  the 
apartment  or  tenement  variety,  restrict  the  amount  of  sunlight 
available  to  adjacent  buildings  as  well  as  to  the  street.  Accord- 
ingly provision  should  be  made  to  regulate  the  heighth  of  build- 
ings in  proportion  to  the  width  of  the  street  they  face.  No 
interior  rooms  should  be  occupied  as  living,  sleeping  or  working 
rooms,  which  do  not  have  outside  windows. 

Large  windows  permitting  the  introduction  of  the  maximum 
of  sunlight  and  fresh  air  are  desirable.  Attention  should  be 
paid  to  the  location  of  the  windows  on  opposite  sides  of  the 
dwelling,  as  well  as  the  location  of  intermediate  doors  and  win- 
dows, so  that  free  passage  of  air  across  the  house  can  be  secured 
when  the  windows  are  open. 

Artificial  illumination  is  of  course  necessary  for  nights  and 
dark  days.  Various  methods  are  now  available,  from  the 
candle,  kerosene,  gasoline,  or  acetylene  lamps  to  gas  and 
electricity.  Electricity  is  probably  the  best  when  available, 
since  the  fire  danger  is  the  least,  it  does  not  consume  oxygen 
from  the  air  and  the  most  brilliant  illumination  is  possible. 


DOMESTIC    SANITATION  297 

The  recent  introduction  of  indirect  illumination  by  means  of 
light  rays  reflected  upon  the  ceiling  from  concealed  globes  is 
undoubtedly  the  best  means  of  artificial  illumination.  The 
room  is  lighted  by  a  diffused  glow,  more  nearly  imitating  natural 
illumination  than  any  other  means.  Eye  strain  is  avoided  if 
those  seated  in  the  room  so  place  themselves,  or  the  lights  are 
so  situated,  that  the  direct  rays  do  not  fall  on  the  face.  Those 
reading  or  doing  work  which  requires  close  inspection  should 
preferably  seat  themselves  so  that  if  right  handed,  the  light 
falls  over  the  left  shoulder.  Delicate  work  should  be  brightly 
illuminated  by  shaded  lamps,  in  addition  to  those  shedding  a 
diffuse  light  over  the  apartment  as  a  whole. 

HEATING  AND  VENTILATION 

These  questions  have  already  been  discussed  in  detail.  We 
shall  only  refer  here  to  the  attention  which  should  be  paid  to 
the  sleeping  quarters  when  in  use.  Otherwise  the  stagnation 
of  air  in  the  breathing  cone  and  the  breathing  zone  will  become 
very  marked.  Every  provision  should  be  made  to  permit  the 
freest  entrance  of  fresh  air.  The  open  air  sleeping  porches 
possess  a  distinct  hygienic  value.  If  asleep  in  a  room  the  air  of 
which  is  stagnant  or  sluggish,  the  concentration  of  the  expired 
air  in  the  breathing  cone  and  the  breathing  zone  reaches  a 
maximum,  due  to  the  fact  that  an  individuals  relative  position 
changes  but  slightly  while  at  rest.  The  greater  the  motion  of 
the  air  the  less  will  be  the  stagnation  of  the  air  in  these  zones. 
Outdoor  sleeping  is  of  a  distinct  advantage  in  the  prevention  and 
treatment  of  tuberculosis.  One  may  safely  enjoy  it  at  a  tem- 
perature considerably  below  zero  by  providing  sufficient  bed 
covers  and  a  hood. 

OVERCROWDING 

Hygienically  there  is  little  in  the  tenement  or  apartment 
house  that  is  fundamentally  sound.  The  ideal  dwelling  is  a 
separate  and  distinct  structure  for  the  housing  of  each  familial 
unit.  The  former  are  only  economically  justified  by  the  high 
price  of  building  land.  Too  often  we  find  that  expense  in  this 
connection  leads  to  a  reduction  in  the  floor  space  of  the  apart- 
ment designed  for  only  one  family  to  the  point  where  the  occu- 
pants are  constantly  in  each  others  society.  Where  rents  are 
high  this  objectionable  factor  is  intensified  by  the  question  of 
sub-leasing  rooms  to  other  individuals  or  families,  as  a  conse- 


298  PRACTICAL    PREVENTIVE    MEDICINE 

quence  of  which  the  overcrowding  is  intensified.  Thus  it  is  not 
uncommon  to  find  a  single  family  with  perhaps  three  or  four 
children  occupying  only  a  single  room  or  perhaps  renting  a  por- 
tion of  their  altogether  inadequate  space  to  another  individual 
or  family.  Under  these  conditions  of  over  crowding,  all  ages 
and  sexes  must  lead  a  life  of  the  greatest  intimacy;  privacy  is  im- 
possible and  immoral  acts  or  sexual  precocity  are  stimulated. 
Adequate  ventilation  does  not  usually  exist,  opportunities  for 
the  transfer  of  human  secretions  and  excretions  reach  a  maxi- 
mum and  consequently  contact  transfer  is  always  favored.  A 
safe  rule  is  to  consider  that  each  space  occupied  as  a  dwelling 
should  provide  at  least  one  room  for  each  member  of  the  family, 
and  not  less  than  one  room  for  each  two  individuals. 

EXCRETA  DISPOSAL 

We  will  not  consider  this  question  from  the  standpoint  con- 
sidered previously.  The  prompt  and  regular  elimination  of 
the  feces  and  urine  bears  an  important  relationship  to  health. 
Irregularity  in  these  habits  promotes  constipation,  and  also  the 
absorption  of  toxins  from  the  fecal  residue  that  impair  health 
and  mental  efficiency.  Consequently  the  education  of  an 
individual  in  the  regular  evacuation  of  the  bowels,  with  most 
persons  at  least  once  daily,  is  of  great  importance.  This  is 
facilitated  by  providing  a  place  for  the  evacuation  of  the  bowels 
and  bladder  kept  suitably  clean  and  inoffensive,  and  where  an 
individual  is  not  exposed  to  extremes  of  temperature  or  incle- 
ment weather.  The  indoor  closet  must  be  regarded  as  a  great 
improvement  in  domestic  sanitation  and  one  which  has  well 
nigh  reached  perfection.  Any  of  the  types  of  water  flush 
closets  on  the  market  at  present  may  be  regarded  as  satisfactory. 
While  the  operation  of  these  is  dependent  upon  an  abundant 
supply  of  running  water,  yet  those  whose  homes  are  without 
running  water  can  avail  themselves  of  the  convenience  of  indoor 
facilities  for  the  discharge  of  the  excreta.  One  of  the  best 
means  for  this  purpose  are  the  so-called  chemical  closets,  in 
which  the  excreta  are  received  in  a  pail  or  tank  of  caustic  solu- 
tion, which  effects  their  disintegration  and  disinfection.  These 
however  are  not  automatic  and  require  attention. 

If  neither  of  these  means  are  available,  the  pit  privy  suitably 
located  with  regard  to  the  water  supply,  must  be  regarded  as 
the  next  best  substitute.  It  should  have  a  water  tight  pit 
or  vault,   and  be  of  fly  proof  construction.     Various  types  of 


DOMESTIC    SANITATION  299 

privies  have  been  designed  and  have  given  varying  degrees  of 
satisfactory  service.  All  that  are  water  tight  and  fly  tight  will 
probably  give  satisfactory  and  safe  service  if  properly  attended, 
though  some  require  frequent  attention,  especially  the  changing 
of  the  receptacles  for  the  receipt  of  the  excreta.  Since  such 
details  are  apt  to  be  neglected  and  hence  interfere  with  the 
satisfactory  operation  of  the  privy,  the  types  recommended 
above  are  best  as  they  require  the  least  attention. 

Isolated  rural  dwellings  that,  have  a  supply  of  running 
water  may  enjoy  the  advantages  of  an  indoor  closet.  The 
sewage  may  be  received  into  a  leaching  cesspool  or  septic  tank, 
preferably  the  latter,  the  overflow  from  which  is  disposed  of  by 
sub-surface  irrigation.  Such  disposal  methods  must  be  care- 
fully located  with  regard  to  the  domestic  water  supply. 

SCREENING 

All  doors  and  windows  at  least  should  be  covered  with  a 
suitable  screen.  For  this  purpose  brass,  copper  or  galvanized 
wire  netting,  of  at  least  18  meshes  to'  the  inch,  is  preferable 
owing  to  its  longer  life.  These  should  be  carefully  fitted  and 
kept  in  repair.  Fire  places  and  chimneys  must  be  scrutinized 
since  it  may  be  necessary  to  screen  these.  It  is  preferable  to 
screen  entire  porches  and  galleries  rather  than  the  windows  and 
doors  opening  out  upon  them.  Before  a  house  can  be  con- 
sidered fly  or  mosquito  tight  it  must  be  ascertained  that  no 
cracks  or  holes  exist  in  the  floors,  walls  or  ceilings  through 
which  these  insects  can  enter. 

PERSONAL  HYGIENE 

Personal  cleanliness  bears  a  very  close- relationship  to  health 
as  we  have  already  seen.  Facilities  for  its  promotion  should 
therefore  be  found  in  every  home.  It  is  perhaps  made  the 
easiest  by  means  of  running  water  and  the  large  porcelain  bath 
tubs  and  wash  bowels  now  available.  Lack  of  these  facilities 
should  however  not  deter  one  from  frequent  cleansing  of  the 
body,  although  the  process  is  made  less  convenient  by  their 
absence. 

THE  KITCHEN 

Two  aspects  of  the  kitchen  demand  our  attention.  The 
first  of  these  is  the  care  devoted  to  the  temporary  preservation 
of  perishable  food,  either  before  or  after  cooking.     Cold  is  the 


300  PRACTICAL  PREVENTIVE  MEDICINE 

means  universally  employed  for  this  purpose.  Where  not 
employed  bacterial  decomposition  may  make  certain  food  stuffs 
unsafe  for  consumption,  especially  milk  for  infant  feeding. 
The  employment  of  ice  in  insulated  boxes  or  cabinets  commonly 
known  as  refrigerators  is  very  common.  In  the  absence  of 
ice,  such  food  is  sometimes  suspended  in  wells,  thereby  jeopardiz- 
ing both  the  food  and  the  well,  or  similarly  suspended  in  pits 
dug  especially  for  this  purpose.  Such  means  will  temporarily 
retard  bacterial  decomposition  until  the  food  is  consumed.  It 
must  be  borne  in  mind  that  the  coldest  situation  in  a  refriger- 
ator is  below  the  ice.  In  the  absence  of  these  facilities,  some 
advantage  may  be  secured  by  placing  the  vessel  obtaining  the 
perishable  food  in  another  vessel  which  in  turn  is  placed  in  a 
vessel  containing  water.  Coarse  cloths  are  placed  over  the 
inner  vessel  extending  down  into  the  water.  The  whole  is  then 
set  in  a  position  where  air  currents  will  cause  the  rapid  evapora- 
tion of  the  water  in  the  cloth,  which  rises  by  capillarity. 

A  second  point  is  the  disposal  of  the  kitchen  refuse  or  gar- 
bage. This  should  be  carefully  drained  to  free  it  from  all 
water,  and  then  wrapped  in  a  paper  before  being  placed  in  the 
garbage  can.  Or  if  a  collecting  service  is  not  available,  it 
may  be  burned  in  a  coal  or  wood  stove,  buried,  or  fed  to  chickens 
or  swine.  It  should  never  be  deposited  upon  the  surface  of  the 
ground  close  to  the  house,  as  it  attracts  flies  and  rats  and  the 
sour  odor  which  develops  during  decomposition  is  very  annoy- 
ing. Toilet  and  washing  facilities  should  be  conveniently 
situated  to  the  kitchen,  especially  where  servants  are  employed. 

REFERENCES 
Overton  and  Denno:  "The  Health  Officer,"  Chapter  XXXVII. 


SECTION  VII 

DEMOGRAPHY 

CHAPTER  XXXV 
STATISTICS  OF  POPULATION 

i.  Demography  may  be  defined  as  the  application  of  statis- 
tical methods  to  the  study  of  populations.  As  such  its  scope  is 
as  broad  as  the  activities  of  mankind.  Our  interest  in  it  is 
exceedingly  narrow,  only  relating  to  those  statistics  which 
indicate  the  changes  and  fluctuations  of  a  population,  as  well 
as  the  degree  of  its  health.  This  narrow  field  of  demography 
is  commonly  designated  as  vital  statistics.  The  subject  of 
statistics  may  be  defined  as  the  numerical  statement  of  facts 
for  study  and  comparison,  and  the  collection  of  data  and  its 
abstraction  for  generalization. 

2.  All  studies  in  vital  statistics  are  based  upon  the  population 
of  the  area  under  consideration,  and  are  necessarily  expressed 
in  terms  of  population.  Statistics  of  population  for  the  pur- 
poses of  vital  statistics  must  show  the  number  of  inhabitants 
of  an  area,  classified  by  age,  sex,  nativity,  race  and  occupation. 
More  detailed  information  would  be  desirable  but  the  labor  of 
making  more  detailed  analyses  is  commonly  too  great  for  the 
available  funds. 

This  fundamental  information  regarding  a  population  is 
obtained  by  a  census  enumeration.  The  standard  census  in  the 
United  States  is  conducted  by  the  Federal  Government.  These 
have  been  taken  every  10  years  since  1790.  In  addition  many 
states  take  decennial  censuses  at  intervals  mid-way  between 
the  years  of  the  Federal  census.  In  order  to  avoid  omissions 
and  errors  it  is  desirable  to  take  the  censuses  at  a  time  of  the 
year  when  the  maximum  number  of  individuals  will  be  at  their 
homes.  The  spring  is  considered  the  best  time  of  the  year  for 
this  purpose.  Actually  the  census  canvas  requires  several 
months  for  its  accomplishment,  yet  for  simplicity  sake  it  can 
be,  and  is  referred  to  a  given  date.  Thus  the  1910  census  was 
referred  to  April  15th. 

301 


302 


PRACTICAL   PREVENTIVE   MEDICINE 


Of  errors  in  census  enumerations,  the  most  important  are  the 
following:  (i)  Overlooked  persons.  It  is  not  possible  to 
require  that  the  entire  activities  of  a  nation  be  suspended  while 
the  great  inventory  is  being  taken.  Some  individuals,  espe- 
cially those  who  are  traveling  are  bound  to  be  overlooked,  others 
may  be  counted  twice  and  unscrupulous  enumerators  or  officials 
in  charge  of  areas  where  a  great  civic  pride  in  rapid  population 
increases  exists,  all  contribute  their  quota  of  error.     On  the 


o50 

a 

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n     u 


3  30 


2  20 


n 

n  n      r 

V 

\l 

0 

n 

LIU 

T. 

II 

*■ 

V 

in 

AGE  DISTRIBUTION 

IN 

MASSACHUSETTS 

FROM  1905  STATE  CENSl 

VOLUME  1,  POPULATIOt 

AND  SOCIAL  STATISTICS,  P 

- 

F 

JS 
i 

555 

UL 

j^ 

^ 

K 

10 


20 


30  40 

Ag&  in  Years 


.50 


60 


70 


80+ 


Fig.   119. — Age    distribution    in    Massachusetts.      (Whipple,    "Vital   Statistics," 
John  Wiley  and  Sons.) 

whole  however,  the  Federal  enumerations  probably  represent 
the  most  accurate  enumeration  possible,  and  the  actual  error 
is  but  a  small  fraction  of  one  per  cent.  These  censuses  should 
always  be  taken  as  the  standard.  (2)  A  second  common  error 
results  from  misstatements  regarding  age.  These  are  of  two 
types.  The  'age  recorded  should  be  the  age  of  the  individual 
at  the  last  birthday.  In  the  case  of  children  up  to  five  it  is 
very  common  to  find  the  stated  age  is  really  the  age  at  the  next 


STATISTICS    OF   POPULATION 


303 


birthday.  On  the  other  hand  adults  show  a  tendency  to  express 
their  age  in  round  numbers,  thus  a  person  of  59  will  give  60  as 
their  age,  or  60  for  62.  As  a  consequence  when  the  population 
is  plotted  according  to  age  we  find  a  great  increase  in  the  num- 
ber of  persons  at  each  of  these  decennial  ages  over  and  above 
those  at  intermediate  ages  (Fig.  119). 


1,200,000 


100,000 


1820"     1830      1840      1850      1860       1870      1880       1890      1900       1910      1920 


Pig.   120. — Immigration  to  the   United  States,   1820-1917.     (Whipple,   "Vital 
Statistics,"  John  Wiley  and  Sons.) 

Populations  are  never  stable,  continuous  fluctuations  is  the 
rule  either  increasing  or  diminishing  (Fig.  123).  The  most 
important  as  well  as  the  most  variable  factor  in  these  fluctua- 
tions are  migrations, .  either  a  moving  out  (emigration)  or  a 
moving  into  an  area  (immigration)  (Fig.  120).  Migratory 
populations  show  a  large  relative  proportion  of  adult  males. 
As  a  result  of  these  changes  we  may  find  that  the  entire  charac- 


304 


PRACTICAL   PREVENTIVE   MEDICINE 


ter  of  a  population  has  changed,  or  its  distribution  within  an 
area  has  been  altered.  Immigration  is  an  important  factor  in 
territory  under-going  industrial  development,  while  emigration 
is  more  commonly  observed  from  areas  of  industrial  stagnation 
or  where  competition  is  keen  and  sharp. 

The  other  constant  factors  in  population  fluctuations  are  the 
increases  resulting  from  births  and  the  losses  arising  from  deaths. 
Where  the  effect  of  migrations  are  not  felt,  a  gradual  increase 
is  usually  observable,  the  increments  from  births  being  usually 
in  excess  of  the  death  losses  (Fig.  121).     On  the  other  hand,  in 


IS75 

I8S0 

t885 

1990 

»95 

BOO 

f9 

X 

810 

£8 

/ 

ft 

/n 

^1 

5 , 

£4 

22 

J 

\ 

s 

K 

i 

s 

£0 

/ 

\ 

/ 

\ 

L 

;e 

\ 

/ 

s 

/ 

r 

18 

1 

\ 

1 — 

/ 

16 

A 

12 

JO 

8 

6 

A 

2 

Fig.   121. — Births  and  deaths  (exclusive  of  stillbirths)  per  1,000  population  per 
annum — Massachusetts — 1871  to  1911.      (Trask:  Suppl.  12,  P.  H.  Rep.) 

some  countries,  such  as  France,  the  death  rate  may  nearly 
coincide  with,  or  at  times  exceed  the  birth  rate  (Fig.  122). 

3.  The  great  expense  of  census  enumeration,  as  well  as  the 
time  necessary  for  the  analysis  of  the  vast  bulk  of  data  secured 
prevent  the  performance  of  annual  enumerations.  Conse- 
quently where  a  population  basis  is  required  for  the  data  of 
the  intercensal  years,  estimates  must  be  employed.  For  this 
two  methods  are  available,  the  arithmetical  and  the  geometrical. 

(a)  Arithmetical  estimation:  This  method  infers  that  a 
constant  yearly  increase  in  the  number  of  the  inhabitants  has 


STATISTICS    OF    POPULATION 


3°5 


taken  place  between  the  censal  years  and  that  the  same  increase 
will  occur  for  some  years  following  the  last  census.  For  employ- 
ment, divide  the  difference  between  the  population  returns 
of  the  censuses  by  the  number  of  years  between  them. 
Multiply  the  quotient  by  the  number  of  desired  years  following 
the  census  and  add  the  result  to  the  proper  census  population. 
Thus  supposing  the  population  of  an  area  was  64,410  in  1890 
and  82,624  m  1900  and  we  desire  to  estimate  the  population  in 
1898  and  1904.     Thus 


Pop.  1900 
Pop.  1890 


82,624 
64,410 


1885 

1990 

1895 

000 

1905 

1910 

26 

24 

& 

in. 

hi 

22 

\ 

\^*^ 

L 

>ec 

th 

5 

% 

/ 

/ 

1 

/* 

\ 

y^ 

<V 

20 

\ 

1 

/ 

\ 

x-s 

-^ 

__ 

-- 

-" 

V  f 

13 

s 
\ 

1 

16 

14 

Fig.  122. — Births  and  deaths  (exclusive  of  stillbirths)  per  1,000  population  per 
annum — France — 1886  to  1911.      (Trask:  Suppl.  12,  P.  H.  Rep.) 


Increase  10  years — 18,214  divided  by  10  equals  1821.4  per 
year.  For  1898  the  population  estimated  would  be  182 1.4 
times  8,  equals  14,571  plus  64,410  equals  78,981.  For  1904,  the 
population  estimates  would  be  182 1.4  times  4  equals  7285  plus 
82,624  equals  89,909.  This  of  course  assumes  that  no  census 
figures  for  19 10  were  available. 

(b)  The  geometrical  estimation  assumes  a  constant  rate  of 
increase.  For  application  the  following  formula  is  commonly 
used: 

Pn  equals  Pc(i  plus  r)n 


Pn 
Pc 


equals  Pc(i  plus  r)n 


20 


3°6 


PRACTICAL  PREVENTIVE  MEDICINE 


For  speed,  logarithms  are  commonly  employed  for  the  solu- 
tion of  the  second  equation  as  follows: 

log.  Pn  —  log  Pc  equals  n  log  (i  plus  r) 

Supposing  that  the  1900  census  gave  an  area  a  population 
of  70,000  and  the  1910  census  100,000  and  we  desire  an  estimate 
of  the  1904  population.     Thus  according  to  our  formula 

Pn  equals  100,000,  whose  log  is  5.000 
Pc  equals  70,000,  whose  log  is  4.851 
5.000  —  4.8451  equals  0.1549 


1770      1780     1790     1800    1810       1620     [830    1840      1850      I860     1870 


1890    1900    1910 


30 

60 

70 

60 

50 

40 

Ji 

<0 

>> 

30 

A 

,  | 

$ 

£0 

V 

nf 

ps 

i\ 

»JS 

10 

Mc 

#. 

s<> 

Fig.  123. — Population  of  the  United  States,  in  millions,  1810  to  1910;  and 
of  Massachusetts,  in  hundred  thousands,  1765  to  1910.  (Trask,  Suppl.  12, 
P.  H.  Rep.) 

0.1549  divided  by  10  equals  0.01549,  the  log.  of  1.036  or 
(1  plus  r)  of  our  formula. 

0.01549  times  4  equals  0.062. 

log.  0.062  plus  log.  4.8451  equals  4.9071,  which  is  the  log  of 
80,750,  the  1904  population. 

Each  of  these  methods  is  best  adapted  to  populations  pre- 
senting certain  characteristics.  The  geometrical  is  best  adapted 
to  populations  whose  increase  is  due  to  the  excess  of  births  over 
deaths,  while  the  arithmetical  is  best  adapted  to  areas  where 
growth  is  largely  due  to  immigration.     The  latter  is  considered 


STATISTICS    OF   POPULATION 


307 


best  adapted  for  use  in  the  United  States.  It  is  to  be  noted  with 
these  two  methods,  that  in  intercensal  years  the  geometrical 
method  will  give  results  less  than  the  arithmetical,  but  for 
postcensal  years  its  results  will  be  greater. 

Where  long  time  estimates  are  required,  such  as  are  required 
for  planning  the  scope  of  public  improvement  for  a  long  term 
of  years,  neither  of  these  are  reliable.  It  is  better  to  compare 
the  area  with  the  development  of  other  similar  areas  but  of 
larger  population,  subsequent  to  the  time  when  their  popula- 
tions were  the  same  as  that  of  the  area  under  investigation. 


I         I  Less  than  50  per  cent  Mai 

ITH150.0  to  51.9 

g%%52.0    ••   53.9 

^^54.0    ••    55.9 

1         I  56.0    ••    57.9 

gll 58.0    ••   59.9 

£SH1  At  least  60  per  cent  Male 

Fig.   124. — Per  cent,  male  in  total  population   for  states  and    territories,    1900 
(Bull.  14.     Bur.  Census.) 

These  methods  are  not  always  applicable,  as  for  example, 
where  a  population  shows  stationary  indications  or  has  even 
declined  at  the  last  census.  Less  accurate  methods  of  estima- 
tion only  are  available  and  these  unfortunately  are  of  no  value 
in  vital  statistics.  Thus  we  may  estimate  the  population 
from  the  ratio  of  persons  per  dwelling,  if  the  number  of  the 
latter  are  known.  For  the  United  States  as  a  whole  this  is  5.2. 
A  dwelling  is  defined  as  any  building  or  set  of  rooms  housing 
a  family.  Or  the  number  of  school  children  or  trolley  passengers 
may  furnish  a  rough  guide. 

4.  The  commonest  data  tabulated  from  census  returns  rela- 
tive to  the  composition  of  the  population  relates  to  sex,  age,  race 


3o8 


PRACTICAL    PREVENTIVE    MEDICINE 


(Fig.  125)  nationality  and  conjugal  condition.  Of  these  age, 
sex  and  race  are  the  most  important  for  use  in  vital  statistics. 
Male  births  are  in  excess  of  female  in  proportion  of  21:20,  but 
male  deaths  are  in  excess  of  female  deaths.  The  greater  migra- 
tory habits  of  males  leads  to  a  diminution  in  the  relative  pro- 
portion of  the  sexes  in  older  communities,  so  that  females  are  in 
excess.  Conversely  in  newly  settled  areas  males  will  predom- 
inate (Fig.  124). 

5.  Another  population  distinction  of  importance  from  our 
standpoint  relates  to  the  distinction  between  urban  and  rural 


1      1  Les9  than  1  per  cent. 

v.*>;a  1  to  5  per  cent. 

E5553  S  to  12  j  per  cent. 

ESS  12J  to  26  per  cent. 

km  25  to  37  J  per  cent. 

Effl  37}  to  50  per  cent. 

IB  50  per  cent  and  over. 

The  heavy  lines  (■»)  show  geographic  divisions. 


Pig.   125. — Percentage  negro  in  total  population  by  states,    1910. 

Bur.  Census.) 


(Bull.  129. 


populations.  Distinction  is  upon  a  purely  arbitrary  basis. 
Thus  in  the  1870  census  towns  of  8000  population  or  less  were 
considered  rural,  in  1880,  4000  or  less  and  in  19 10,  2500  or  less. 
Thus  it  can  be  seen  that  these  distinctions  have  not  been  made 
on  a  constant  basis.  In  the  1870  census  32.90  per  cent,  of  the 
country's  population  was  urban  and  in  the  1880  census  37.3  per 
cent. 

6.  Another  important  point  is  the  determination  of  the 
density  of  population,  that  is,  the  number  of  individuals  per 
unit  of  surface  area.  Most  commonly  for  larger  areas  such 
as  states  and  countries  the  population  is  divided  by  the  total 
area  in  miles  or  acres  (Fig.  126).     For  comparative  studies  in  an 


STATISTICS    OF    POPULATION 


3°9 


urban  population  it  is  perhaps  better  to  analyze  data  according 
to  ward  populations  rather  than  by  density  per  acre. 


In  considering  population  fluctuations  within  civil  areas  in 
successive  years  it  is  important  to  ascertain  if  any  changes  have 
been  made  in  the  geographical  boundaries  of  the  area  under  con- 


310  PRACTICAL  PREVENTIVE  MEDICINE 

sideration.  Large  increases  may  be  due  to  the  annexation  of 
territory  with  a  considerable  population,  and  sudden  increases 
thus  appear. 

6.  Value  of  Vital  Statistics. — In  any  consideration  of  various 
facts  concerning  a  large  body  of  individuals,  such  as  the  popula- 
tion of  a  city,  a  state  or  a  nation  as  regards  births,  deaths  or 
individuals,  it  is  impossible  to  consider  the  individual  by  him- 
self, but  rather  all  must  be  considered  in  the  aggregate  if  any 
clear  conception  is  to  be  gained  of  the  influence  of  economic  or 
morbific  factors.  Considered  as  individuals  we  would  lose 
sight  of  the  mass.  As  a  consequence,  it  is  necessary  to  employ 
statistical  methods  to  avoid  confusion  and  to  enable  the  trend 
of  events  to  be  clearly  discerned. 

In  any  employment  of  statistical  methods  it  is  of  course 
necessary  to  express  facts  by  figures,  and  as  expressed  by  Whip- 
ple: "When  figures  are  used  to  express  facts,  and  when  logical 
processes  are  applied  to  figures,  divorced  in  the  mind  from  the 
facts  for  which  they  stand,  it  is  easy  for  fallacies  to  creep  in 
without  being  recognized;  it  is  easy  to  compare  things  that 
ought  not  be  compared;  to  generalize  from  inadequate  data 
and  so  commit  all  sorts  of  illogical  errors.  Thus  the  unscrupu- 
lous may  fool  the  unwary  and  the  innocent  fool  themselves. 
Hence  to  use  statistics  properly  one  must  be  able  not  only  to 
visualize  the  facts  but  to  think  logically." 

Quoting  Whipple  further: 

"Vital  statistics  are  useful  for  many  purposes.  To  the  his- 
torian they  show  the  nation's  growth  and  mark  the  flood  and 
ebb  of  physical  life;  to  the  economist  they  indicate  the  number 
and  distribution  of  the  producers  and  the  consumers  of  wealth; 
to  the  sanitarian  they  measure  the  people's  health  and  reflect 
the  hygienic  conditions  of  their  environment;  to  the  sociologist 
they  show  many  things  relating  to  human  beings  in  their  rela- 
tions one  with  another." 

"Vital  statistics  are  not  to  be  collected  and  used  as  mere 
records  of  past  events;  an  even  more  important  use  is  that  of 
prophesying  the  future.  The  health  officer  should  study  them 
as  soon  as  received  and  not  wait  until  some  convenient  day 
when  other  work  is  slack  and  then  merely  tabulate  them  and 
make  averages  for  formal  reports  and  permanent  records. 
Vital  statistics,  especially  those  of  morbidity,  should  be  studied 
in  the  making  and  just  as  the  meteorologist  reads  his  instruments 
daily  in  order  to  forecast  the  weather  and  give  warnings  of  the 
coming  hurricane,  so  the  efficient  health  officer  will  daily  study 


STATISTICS    OF   POPULATION  311 

the  reports  of  new  cases  of  disease  in  order  that  he  may  be  fore- 
warned of  an  impending  epidemic  and  take  measures  to  check 
its  ravages." 

REFERENCES 

The  Story  of  Census,  1790-1916.     Bureau  of  the  Census. 
Federal  Estimates  of  Population  and  Federal  Supervision  of  Local  Censuses. 
Bureau  of  the  Census. 


CHAPTER  XXXVI 

STATISTICS  OF  BIRTHS  AND  DEATHS 
BIRTH  STATISTICS 

Birth  records  are  secured  by  registration  in  those  civil  divi- 
sions that  secure  sufficiently  complete  records  to  be  of  value. 
Legal  responsibility  is  placed  upon  physicians  and  mid- wives  to 
make  reasonably  prompt  returns  in  accordance  with  prescribed 
rules  and  upon  special  forms  (Fig.  127),  to  designated  officials. 
The  securing  of  reasonably  complete  birth  records  is  a  difficult 
matter  and  at  least  in  the  United  States  is  probably  nowhere  100 
per  cent,  complete. 

Birth  records  are  of  value  to  individuals  whose  births  are 
recorded  from  the  standpoints  of  giving  legal  proof  of  citizen- 
ship, age  and  parentage,  all  of  which  are  sometimes  necessary 
to  secure  passports,  residence,  to  secure  employment,  to  prove 
legitimacy,  to  inherit  property  and  in  numerous  other  ways  to 
enable  an  individual  to  enjoy  the  rights  of  citizenship.  From 
a  public  health  standpoint  birth  registration  is  of  importance 
as  it  enables  health  authorities  to  intelligently  combat  infant 
mortality  by  means  we  have  already  considered. 

All  children  who  breathe  after  birth  should  be  registered  as 
births,  while  still  births  should  not  be  recorded  in  either  the 
groups  of  births  or  deaths,  but  placed  in  an  independent  group. 

A  rough  check  on  the  completeness  of  registration  may  be 
secured  by  comparing  the  total  number  of  births  registered  by 
the  number  of  children  under  1  year  of  age  enumerated  in  any 
census  year. 

The  births  in  a  given  population  may  be  expressed  for  com- 
parative purposes  in  the  following  ways: 

(a)  The  rate  or  number  per  1000  of  the  entire  population. 

(b)  The  rate  per  1000  women  of  child  bearing  age  (15-45). 

(c)  The  legitimate  birth  rate  per   1000  married  women  of 

15-45- 

(d)  The  illegitimate  birth  rate  per  1000  unmarried  women 

of  15-45- 

The  first  of  these  methods  of  expression  is  known  as  the  crude 
birth  rate,  and  is  subject  to  the  same  objections  when  employed 
for  comparative  purposes  that  are  raised  to  the  crude  death 

312 


STATISTICS    OF   BIRTHS    AND    DEATHS 


313 


rate.     These  will  be  considered  later.     These  rates  are  com- 
puted in  the  same  manner  as  the  death  rates,  as  shown  later. 

United  States  Standard  Certificate  of  Birth. 


*•  u    « 

»       «  1 

e  t-     s 

I  0  5  - 

I  z  5  3 

r  q  Z  E 

Z  Z  u  e  » 

I  5  «  I1. 

«  u.  =  «  ? 

S  u  J  «  : 
1  >  -  ■•: 

s  u  *  =1 
-e  C  s  3  e 

=•0*5- 
Ms! 

3      a.  .; 

I  I! 

1 

5,!   * 


PLACE  OF  BIRTH 

County  of .....  .... 

Township  of 1 

Village  of ■— 

FULL  NAME  OF  CHILD 


STANDARD  CERTIFICATE  OF  BIRTH, 


Registered  No. — .- 


....Ward) 

[f-ciltd  tioot  ;tt  D*a«j,  E*k« 
iappiemtsUMi  Terpen,  uiirecteA 


Sex  of 

Child 

1    T>b,tripM, 
1      v  other! 

1                 <T.b..r.«.««looi;i 

Nombarla  order 
of  birth 
rjerartafiJanlMr. 

h») 

\±, 

J        birth.     .       .— ,- 

-,19 

FULL 
NAME 

FATHER 

FULL 

MOTHER 

RESIDENCE 

RESIDENCE  - 

COLOR 

AirR^^vsT 

-Srj-" 

COLOR 

AOE  AT  LAST 
BIRTHDAY 

-       -n 

BIRTHPLACE 

BIRTHPLACE 

OCCUPATION 

OCCUPATION 

NumUr  of  childrc 

U,;.m=,h«-.W^«p,„».^> 

of  ffctl 

CERTIFICATE  OF  ATTENDING  PHYSICIAN  OR  MIDWIFE* 


I  hereby  certify  that  I  attended  the  birth  of  this  child,  who  * 
the  data  above  stated. 

(Signature)  . 


.  should  maJce  this  re 
e  of  life  aftr, 


(I-tjtician  cr  Midwife) 


no  added  from   a  supplemental      Address— 


2  II 


SUPPLEMENTAL 

(Thii  r 

(SI 

Place  of  birth 

« 

(Ee^irtra 

Hon  dtatr.rt) 

SEX  OF  CHILD' 

Twin." 

triplet, 

H 

Nraber" 
rfffirtt 

(D.7)           (T«M] 

! FULL* 

FATHER 

'  NAME 

FULL' 
MAIDEN 

MOTHER 

■ 

*  wwrcl  tj  l 

<-"-**"**" 

IS"'°8°"U"*'°m' 

)  nude  ikr.  original) 

Registered,  Number  * .... 


I  HEREBY  CERTIFY  that  the  child  described  herein  has 


Fig.   127. —  (Trask,  Suppl.  12.     P.  H.  Rep.) 

The  second  method  of  expression  gives  a  better  idea  of  the 
fecundity  of  a  population,  while  the  third  and  fourth  methods 


314  PRACTICAL   PREVENTIVE    MEDICINE 

when  used  together  give  a  still  better  idea.  These  should  be 
employed  when  it  is  desired  to  compare  the  births  in  one  com- 
munity with  those  of  another. 

The  frequency  of  births  varies  widely  with  different  races 
and  nationalities,  in  different  parts  of  a  country,  state  or  even 
a  city.  The  crude  rate  may  vary  in  the  extreme  from  22  to 
39  per  thousand.  The  following  factors  influence  the  birth 
rate:  (a)  the  age  distribution  of  the  population;  (b)  the  propor- 
tion of  the  two  sexes;  (c)  the  number  of  first  marriages;  id) 
the  age  at  marriage;  (e)  the  economic  condition  of  the  country, 
and  (/)  social  and  hygienic  conditions. 

MORTALITY  STATISTICS 

Death  records  are  likewise  secured  by  registration.  On 
the  other  hand,  it  is  fairly  easy  to  secure  complete  returns  if  a 
death  certificate  is  required  before  a  burial  permit  is  issued. 
The  death  certificate  (Fig.  128),  a  portion  of  which  dealing  with 
the  cause  of  the  death  is  filled  out  by  the  attending  physician, 
is  filed  with  the  proper  authorities  by  the  undertaker. 

Errors  are  not  uncommon  on  these  certificates  and  the 
authorities  should  require  their  correction  before  certificates 
are  accepted.  The  original  data  may  be  incorrect,  due  to  mis- 
statements by  members  of  the  decedent's  family.  The  state- 
ment of  the  cause  of  death  given  by  the  physician  may  be 
inaccurate  due  to  an  erroneous  diagnosis  or  a  desire  to  shield 
the  feelings  of  the  decedent's  family. 

One  of  the  most  important  aspects  of  the  physician's  obliga- 
tions in  connection  with  mortality  reporting  is  the  statement 
concerning  the  cause  or  causes  of  death.  Two  grave  errors 
are  possible  which  seriously  interfere  with  the  accuracy  of 
mortality  returns.  The  first  of  these  possible  errors  relates 
to  mistakes  in  the  diagnosis  of  the  condition  actually  responsible 
for  death.  Any  physician  who  has  followed  a  considerable 
series  of  cases  to  postmortem  is  familiar  with  the  fact  that  post- 
mortem examinations  not  infrequently  fail  to  corroborate  the 
antemortem  diagnosis,  even  when  the  patient  had  been  under 
the  care  of  extremely  competent  physicians.  Where  the  post- 
mortem examination  serves  as  a  check  these  errors  are  usually 
revealed,  but  where  postmortem  examinations  are  not  made, 
and  relatively  few  bodies  are  examined  postmortem,  these 
errors  remain  concealed.  Another  source  of  error  is  the  em- 
ployment by  physicians  of  vague  or  inaccurate  terms  in  stating 


STATISTICS    OF  BIRTHS    AND   DEATHS 


3*5 


the  cause  of  death,  so  that  it  is  difficult  to  associate  the  stated 
cause  with  any  definite  pathological  condition.  The  first  of 
these  possible  errors  can  only  be  reduced  by  greater  refinements 
in  the  art  of  diagnosis  and  of  greater  efficiency  on  the  part  of 
the  medical  profession  in  their  application.  The  second  can 
be  reduced  by  care.  The  Census  Bureau  is  endeavoring  to 
secure  an  improvement  in  the  last  direction  by  familiarizing 
physicians  with  the  standard  International  Lists  of  Causes  of 


132 


S<I 


o   i! 


STANDARD  CERTIFICATE  OF  DEATH 


DEMBTWeMT  OF  COMKXftCE 


1  PLACE  OF  DEATH 
County 


Township  — 
Cfty 


<lt  d^ain  occurred  In  a  hospital  or  Institution  gtve  its  sxm  tested  a 


(a)  Residence.    No. . 

( Usual  place  of  al 


H-*1i-glnU.  S-.  'fcff-a-tlgn  b'--tti7 


irwrtflmt  give  cttj  o 


PERSONAL  AND  STATISTICAL  PARTICULARS 


MEDICAL  CERTIFICATE  OF  DEATH 


4  COLOR  OR  RACE     5 


16  DATE  OF  DEATH  ^c 


I.  widowed,  or  divorced 


|  6  DATE  OF  BIRTH  (month,  day,  and  year) 


partialis  >  -  i  of  »;■'._— 
CM  fimril  nxhire  of  lednttry, 


Z   •  *   • 

iH. 

SHI 


;RE BY  C e  RT l  F"  V,  That  I  attended  deceased  from 


lat  1  last  5 

nd  that  de 


CONTRIBUTORY- 


18  V 


10NAMEOFFATHER 


£  j  5  I  12  MAJDEN  NAME  OF  MQTHER 


Did  an  operation  precede  death  7 

Was  there  an  autopsy? 

What  test  confirmed  diagnosis  ?  . 

(81  gned) 

,  19     (AdoVe*) 


12  BIRTHPLACE  0FM0THER(dt7 or  toirn). 


HoioasAi-    (Sm  r 


e  side  for  additional  space.) 


ACODXBT1L,  BUlTTTur,  or 


19  PLACE  OF  BURIAL,  CREMATION,  OR  REMOVAL     DATE  OF  BURIAL 


20  UNDERTAKER 


Fig.  128. 

Death,  and  also  the  indefinite,  objectionable  terms  whose  use 
should  be  avoided.  The  Bureau  publishes  a  very  convenient 
Docket  list  of  the  proper  terms. 

Death  records  serve  the  following  purposes;  (a)  they  aid  in 
the  detection  of  crime,  making  the  concealment  of  murders 
very  difficult;  (6)  assist  in  the  transfer  of  inherited  property; 
(c)  facilitate  the  settlement  of  life  insurance,  and  lastly  (d)  in- 
dicate the  extent  and  changes  in  population  produced  by  death. 
From  a  public  health  standpoint  they  have  some  value  in  the 


316 


PRACTICAL   PREVENTIVE    MEDICINE 


control  of  disease,  especially  where  morbidity  reporting  does 
not  exist.  Their  greatest  drawback  in  this  connection  is  due 
to  the  fact  that  the  information  they  give  is  tardy  and  also' 


incomplete  from  the  standpoint  of  revealing  all  disease  in- 
cidence. A  greater  value  they  possess  in  this  connection  is  in 
permitting  a  certain  check  to  be  made  on  the  completeness 
of  morbidity  reports. 


STATISTICS    OF   BIRTHS    AND    DEATHS 


517 


Deaths  among  a  given  population  are  expressed  in  rates 
fundamentally  similar  to  those  employed  in  expressing  births. 
The  most  common  rate  employed  is  the  general  or  crude  death 
rate.  This  may  be  defined  as  the  ratio  of  the  number  of  deaths 
within  a  given  time  to  the  number  of  people  alive  at  the  middle 
of  the  period,  referred  to  some  round  number  (1000,  10,000  100,- 


GENERAL  DEATH  RATES  OF  THE  UNITED  STATES  (REGISTRATION  AREA)  AND  CERTAIN  FOREIGN  COUNTRIES 
FOR  EACH  OF  THE  YEARS  FROM  1900  TO  1914. 


912  1913         1914 


Fig.   130. — {Mortality  Statistics,  IQI5>  Bur.  Census.) 

000)  as  a  basis  for  comparison.  The  period  commonly  chosen 
is  one  year.  In  estimating  populations  for  this  purpose  it  is 
necessary  to  estimate  the  mid-year  population,  making  suitable 
corrections  with  the  census  figures  for  the  dates  to  which  they 
have  been  referred.  Their  precision  depends  upon  the  accuracy 
of  the  population  and  death  figures. 


3i8 


PRACTICAL    PREVENTIVE    MEDICINE 


They  are  computed  as  follows: 

A  population  of  60,000  has  in  one  year  900  deaths.     What  is 
the  crude  death  rate  per  1000? 
Method  A. 

900 


Method  B. 


60,000 


900 


X  1000  =  15 


60,000 


1000 


=  i5 


240 


220 


200 


180 


160 


140 


£120 


100 


80 


60 


40 


20 


SPECIFIC  DEATH  RATES 

OF 

MALES  AND  FEMALES 

IN 

ORIGINAL  REGISTRATION  STATES 

1910 

FROM  U.S.  LIFE  TABLES  PREPARED 

BY    PROF.  JAMES.  W.  GLOVER,  FOR 

THE  BUREAU   OF  THE  CENSUS,  1916 

/ 

f 

r 

1 

1 

$ 

1 

9  f 

? 

4 

/» 

li 

r* 

// 

1 

1 

y6 

I 

* 

.*. 

w^- 

3^ 

0 

1 

0 

2 

] 

'6 

J 

4 

0 

5 

0 

6 

J 

7 

0 

& 

3 

9 

0 

100 

Age  in  Years 

Fig.  131. — Specific  death  rates  of  males  and  females.     (Whipple,  "Vital  Statis- 
tics," John  Wiley  and  Sons.) 


Their  most  common  use  is  in  a  comparison  of  the  mortality  in 
the  same  community  in  different  years,  or  between  two  com- 


STATISTICS    OF  BIRTHS    AND   DEATHS 


319 


munities  having  similar  populations.  If  the  crude  rate  is  em- 
ployed in  making  comparisons  between  two  communities  having 
similar  populations,  falacious  conclusions  will  almost  certainly 
be  drawn.  For  this  purpose  special  rates  should  be  employed 
of  which  we  will  shortly  speak  (Fig.  130.) 

It  is  sometimes  desirable  to  compute  the  death  rates  for  short 
periods,  such  as  weeks,  months  or  quarters.  When  so  com- 
puted these  are  expressed  in  terms  of  annual  rates,  i.e.  as  what 
the  annual  rate  would  be  providing  the  deaths  occurred  through- 
out the  year  with  the  same  frequency  as  during  the  week  or 
month  under  consideration. 

Another  type  of  death  rates  frequently  computed  are  the 
so-called  specific  rates.  These  are  the  rates  for  specific  or 
limited  groups  of  the  population,  such  as  those  of  age,  sex,  social 
condition,  occupation,  etc.  They  are  stated  as  the  proportion 
of  the  number  of  deaths  per  annum  in  the  sub-group  per  1000 
of  the  mean  annual  number  of  the  population  in  that  sub- 
group. The  groupings  of  age  and  occupation  are  most  com- 
monly employed  (Fig.  131).  The  expression  of  births  according 
to  women  of  child  bearing  age  may  be  considered  a  specific 
birth  rate.  They  are  the  computations  which  should  be  em- 
ployed for  purposes  of  comparison  or  to  secure  a  true  insight 
into  the  prevalence  or  incidence  of  different  diseases.  Their 
computation  can  be  readily  understood  from  the  following 
example.  Divide  the  number  of  deaths  of  persons  whose  ages 
lie  within  the  age  groups  employed,  by  the  number  of  thou- 
sands of  persons  alive  in  the  same  groups  at  the  mid-year. 
Thus: 

TABLE  XII 
Boston  Deaths  by  Age  Periods  for  1912 


Age  groups 


Number  of 
deaths 


Estimated 
population  in 
each  age  group 


Specific  death 
rate   (iooo) 


Under  1 . . . . 

1-19 

20-39 

40-S9 

60  and  over 

Total.  .  .  . 


2,186- 
i,39i- 
2,017- 
2,771- 

3,274- 


14,550 
234,100 
273,400 
154,000 

47,4oo 


150 

5 

7 

17 

68 


11,639 
(total  deaths) 


724,175 
(total  popu- 
lation) 


16.17 
(crude) 


32° 


PRACTICAL    PREVENTIVE    MEDICINE 


A  still  better  method  to  employ  for  comparative  purposes 
is  the  standardized  or  corrected  death  rate.  This  is  based  upon 
a  standard  or  stable  population,  not  affected  appreciably  by 
migratory  factors.  The  Swedish  census  of  1890  which  had  5 
age  groups,  or  the  standard  million  of  England  and  Wales  of 
1 901  with  eleven  age  groups  further  subdivided  according  to 
sex,  are  most  commonly  used  as  a  base.  The  standard  Swed- 
ish population  is  divided  per  1000  as  follows: 


Under 

1 

25 

•5 

1-19 

398 

0 

20-39 

269.6 

4o-59 

192 

3 

60  and 

over 

114 

.6 

The  method  is  employed  as  follows:  Compute  the  specific 
death  rates  of  the  several  age  groups  of  the  population  whose 
standardized  death  rate  it  is  desired  to  obtain  (Table  XII). 
Then  take  the  corresponding  age  groups  in  the  standard  popula- 
tion and  compute  the  number  of  deaths  that  would  have  occurred 
in  each  age  group  at  the  specific  death  rate  found  to  exist  in  the 
population  for  which  the  standard  death  rate  is  being  computed. 
Add  the  number  of  deaths  which  it  is  thus  found  would  have 
occurred  in  the  age  groups  of  the  standard  population.  This 
gives  the  standardized  rate  per  1,000,000.  The  rate  per  1,000 
is  secured  by  dividing  this  by  1 ,000. 

We  may  exemplify  this  by  continuing  the  employment  of  the 
Boston  data  already  given. 


TABLE  XIII 

Application  of  Corrected  Death-rate,  Boston,  191 2 


Age  group 


Specific  death 
rate 


Standard  age 

distribution 

(Swedish) 


Corrected 
death  rate 


Under  i..  .  . 

I-I9 

20-39 

40-S9 

60  and  over 


150 

5 

7 

17 


5  X 
93  X 
35  X 
95  X 
8   X 


25.54-1,000 

3- 

398.04-1,000 

2. 

269. 6-5- 1,000 

1 . 

192  .34-1,000 

3- 

114.64-1,000 

7- 

Corrected  death  rate :    19.45 


STATISTICS    OF  BIRTHS    AND    DEATHS  321 

This  is  seen  to  be  considerably  higher  than  the  crude  death 
rate  of  16.17  °f  our  previous  computation.  Their  value  for 
comparative  purposes  is  further  shown  in  the  following  table: 


Cambridge,  Mass. 

Chicago 

Crude  death  rate 

15.2 
14-5 

14-5 
16.4 

Standardized  death  rate 

With  the  employment  of  only  the  crude  rate  erroneous  im- 
pressions might  be  drawn. 

Death  rates  are  influenced  by  the  following  factors:  (a) 
Statistical  methods  employed  in  their  computation,  (b)  The 
age,  sex  and  social  composition  of  the  population,  (c)  The 
number  and  size  of  hospitals  and  institutions  for  the  care  of 
the  sick  and  aged  within  the  area,  (d)  Migration,  (e)  Hygienic 
and  sanitary  conditions.     (/)  The  birth-rate. 

INFANT  MORTALITY 

The  expression  of  infant  deaths  is  a  difficult  matter.  Three 
methods  are  employed  and  each  has  disadvantages.  They  are 
as  follows: 

(a)  As  a  ratio  between  the  number  of  deaths  under  1  year 
of  age  in  1  year,  and  the  number  of  births  within  the  same  year, 

thus  -p.    ,  It  is  known  as  "Infant  Mortality."     Its  inac- 

curacy lies  in  incomplete  birth  returns. 

(b)  As  a  ratio  between  the  number  of  deaths  in  the  calendar 
year  under  1  year  of  age  and  the  number  of  children  under  1 
year  on  July  1st  of  the  calendar  year.     It  is  really  the  specific 

death  rate,  thus^— ; — 7— : — .     Its  inaccuracy  is  likewise 

Infant  population 

due  to  incomplete  birth  returns. 

(c)  As  a  ratio  between  the  number  of  deaths  under  1  year 
and  the  total  deaths  at  all  ages.  This  ratio  is  subject  to  fluctua- 
tions not  related  to  infant  mortality. 

REFERENCES 

Rosenau:  Preventive  Medicine  and  Hygiene,  3rd  ed.,  pp.  101 7-1033. 
Physician's   Pocket   Reference  to  the  International  List  of  Causes  of  Death. 
Bureau  of  the  Census. 
21 


322  PEACTICAL   PREVENTIVE    MEDICINE 

Birth  Registration:  Monograph,  Children's  Bureau. 

The  Federal  Registration  Service  of  the  United  States.     Bureau  of  the  Census. 

Whipple:  Vital  Statistics. 

Vital  Statistics:  Supplement  12,  Public  Health  Reports. 

Standard  Certificate  of  Birth  and  Correctionary  Supplement. 

Standard  Certificate  of  Death. 

Annual  Reports  on  Mortality  Statistics  and  Birth  Statistics  of  the  Census 

Bureau,  1900. 
The   Accuracy   of   Certified    Causes   of   Death.     Reprints,   363,   440,  Public 

Health  Reports. 


CHAPTER   XXXVII 
STATISTICS  OF  SICKNESS 

i.  From  the  standpoint  of  public  health,  statistics  of  sickness 
or  morbidity  statistics  are  the  vital  statistics  of  greatest  im- 
portance. These  show  the  occurrence  of  disease  and  its  rela- 
tive prevalence  in  different  localities  and  at  different  times. 

This  information  is  primarily  secured  by  a  system  of  report- 
ing cases  of  illness  known  as  notification.  The  responsibility  for 
making  these  reports  is  primarily  placed  on  the  practicing  phy- 
sicians, and  to  a  lesser  extent  on  the  householder  or  family 
head  in  the  absence  of  an  attending  physician.  Laws  or  regula- 
tions requiring  these  reports  should  specify  that  all  real  or 
suspected  cases  or  carriers  should  be  reported  within  24  hours  of 
their  recognition  or  suspicion.  Reports  may  be  either  by  phone 
or  mail,  but  the  former  method  should  always  be  confirmed 
in  writing.  As  previously  brought  out,  modern  methods  of 
disease  control  are  based  upon  a  prompt  knowledge  of  how, 
when  and  where  cases  of  preventable  diseases  are  occurring. 
Consequently  physicians  in  submitting  their  reports  to  health 
authorities  are  rendering  a  very  important  service  in  disease 
control 

In  this  country  the  so-called  model  morbidity  law  now 
furnishes  the  basis  for  most  reporting  of  this  character.  While 
adequate  penalties  should  be  provided  for  failure  to  make  the 
necessary  reports,  yet  health  authorities  will  find  it  advantage- 
ous to  make  reporting  as  easy  as  possible  for  busy  practitioners. 
One  very  helpful  aid  in  this  connection  is  the  printing  of  re- 
port blanks  on  post  cards  and  keeping  the  physicians  adequately 
supplied  with  these  (Fig.  132).  The  communicable  diseases 
were  the  first  group  whose  reporting  was  generally  required, 
and  in  addition  we  frequently  find  the  occupational  diseases 
in  these  lists  and  sometimes  cancer  and  pellagra.  The  follow- 
ing considerations  should  govern  health  authorities  in  selecting 
diseases  to  be  placed  upon  the  reportable  list: 

1.  The  disease  should  be  one  of  public  health  importance 
either  from  the  standpoint  of  causing  death  or  disability. 

2.  It  should  be  a  disease  whose  means  of  prevention  are  fully 
understood  and  which  may  be  effectively  combatted,  or 

323 


324 


PRACTICAL    PREVENTIVE    MEDICINE 


3.  One  for  which  highly  effectively  prophylactic  or  thera- 
peutic agents  exist.  Thus  cases  of  dog  bites  should  be  reported 
not  because  rabies  spreads  from  man  to  man,  but  because  prompt 
immunization  will  protect  the  person  bitten  from  possible  rabies 
in  the  biting  animal. 

4.  If  the  disease  is  of  itself  trivial  or  unimportant,  it  may  be 
indirectly  of  importance.  Such  as  for  example  the  confusion  of 
chicken-pox  with  mild  small-pox  or  German  measles  with  scarlet 

fFaceofCardri 

,191... 

(Date.) 

■Dlsease.or  suspected  disease . .,..#..-.... 

iPatient's  name ,age ,  sex.... . ,  color. „ 

Patient's_address ......  occupation . 

School  attended  or  place  of  employment _ .. 

'Number  in  household:  Adults * * ,  children 

Probable  source  of  infection  or  origin  of  disease ^ 

If  disease  is  smallpox,  type „ ,  number  of  time3 

successfully  vaccinated  and  approximate  dates - 

If  typhoid  fever,  scarlet  fever,  diphtheria,  or  septic  sore  throat,  was  patient,  or  is  any  member  of  household 

engaged  in  the  production  or  handling  of  milk 

Address  of  reporting'j>hysician : '. 

Signature  of  physician 


'Tot  use  of  local  health  department. 
©  o  -4  ■ 


[Reverse  of  card.] 


g  I 

as 


0 

0   I 


Fig.  132 


aj 


3 


s.  t) 


B       5 


Health  Department, 

(City) 

(State) 


-Standard  morbidity  report.     (Trask,  Suppl.  12.  P.  II.  Rep.) 


fever.  These  should  therefore  be  reported  so  that  a  differential 
diagnosis  may  be  made  by  experienced  observers. 

5.  If  an  exotic  disease,  it  should  be  one  that  could  gain  a 
permanent  foothold  if  introduced.  Thus  yellow  fever  should 
be  reportable  in  the  gulf  states  where  stegomyia  mosquitoes 
abound,  but  no  purpose  is  gained  by  placing  yellow  fever  on  the 
list  of  reportable  diseases  in  Montana,  where  stegomyia  is 
not  found. 

Notification  in  order  to  be  of  maximum  value  must  be  as 


STATISTICS    OF   SICKNESS  325 

complete  as  possible.  We  have  already  called  attention  to  un- 
recognized sources  of  infection  which  must  be  sought  out  by  the 
initiative  of  the  health  authorities.  Various  checks  are  em- 
ployed to  indicate  the  degree  with  which  physicians  are  dis- 
charging their  notification  duties.  Thus  all  death  certificates 
in  which  the  ascribed  cause  is  one  of  the  reportable  diseases 
should  be  compared  with  the  morbidity  report  files  to  ascertain 
that  the  death  was  previously  reported  as  a  case.  If  not  so 
previously  reported,  investigation  will  usually  reveal  that 
some  one  has  been  negligent.  Case  mortality  ratios  may  also  be 
used  as  a  check.  Thus  from  every  death  of  typhoid  reported, 
the  morbidity  files  should  reveal  approximately  ten  reported 
cases  of  the  disease.  The  reporting  of  the  recognized  cases 
by  the  physicians  permits  the  health  authorities  to  investigate 
the  contacts  for  missed  cases  and  carriers,  and  thus  detect 
infected  persons  who  would  otherwise  pass  unrecognized  and 
uncontrolled. 

The  data  secured  by  these  reports  should  be  immediately 
classified  and  tabulated  by  the  health  authorities  so  that  the 
maximum  information  will  be  revealed.  They  first  of  all 
should  be  classified  according  to  disease.  Each  case  reported 
should  be  located  upon  a  spot  map  of  the  area.  Summaries  of 
the  total  cases  of  each  disease  reported  by  days,  weeks  or  months 
should  be  kept  constantly  up  to  date,  making  the  necessary  ad- 
ditions to  these  tables  each  day.  Thus  the  health  authorities 
can  constantly  keep  their  fingers  upon  the  pulse  of  disease  preva- 
lence and  instantly  recognize  any  epidemic  in  its  incipiency 
and  in  addition  deal  effectively  with  endemic  disease.  Many 
health  authorities  in  addition  to  the  daily  summaries  above 
noted,  also  daily  post  the  cases  of  diseases  which  may  be  milk- 
borne  against  the  dealer  from  whom  their  milk  was  secured,  and 
thus  they  can  learn  immediately  of  a  milk-borne  outbreak.  If 
these  reports  are  only  used  to  prepare  tables  of  figures  to  show 
past  history  of  disease  prevalence,  very  little  actual  service  will 
result  from  reporting. 

In  general  we  may  say  that  the  morbidity  information  will 
be  put  to  the  following  uses: 

(a)  It  shows  the  geographical  location  of  sources  or  foci  of 
infection. 

.  (b)  Enables  the  health  authorities,  by  the  investigation  of  the 
cases  reported,  to  secure  epidemiological  information  of  occur- 
rence, distribution  and  prevalence  of  disease ;  ascertain  missed 
cases  and  carriers  and  prevent  the  further  spread  of  disease. 

^  (c)  Enables  proper  treatment  to  be  provided  for  those  finan- 
cially unable  to  secure  it. 


326 


PRACTICAL   PREVENTIVE   MEDICINE 


(d)  Indicates  the  necessary  preventive  measures. 

(e)  Gives  the  history  of  a  given  disease  for  a  series  of  years, 
from  which  the  endemic  index  may  be  computed. 

(/)  In  the  case  of  occupational  diseases,  it  shows  the  location 
of  conditions  causing  disease  or  injury. 

For  purposes  of  comparison  morbidity  information  is  ex- 
pressed by  several  rates,  as  follows: 

(a)  The  crude  morbidity  rate.  This  is  the  number  of  cases 
of  a  given  disease  occurring  during  a  year  per  iooo  or  10,000 
of  the  total  population.  This  is  open  to  the  same  disadvantages 
as  crude  rates  in  general. 


1385 

1890 

1895 

1900 

1905 

1910 

s 

6 

7 

/ 

/ 

6 

/ 

\ 

/ 

\ 

£ 

/ 

\ 

1 

4 

3 

Z 

Pig.   133. — Diphtheria.     Number  of  cases  notified  per  annum  for  each  death 
registered — Michigan — 1884  to  1910  (Trask,  Suppl.  12.,  P.  H.  Rep.). 

(b)  The  specific  morbidity  rate.  These  are  of  a  value  similar 
to  specific  death  rates.  Diseases  whose  incidence  is  limited  to 
certain  age  groups  should  also  be  expressed  in  rates  of  the 
number  of  cases  per  iooo  persons  in  the  population  of  that  age 
or  class. 

(c)  Fatality  rates.  These  may  be  expressed  as  the  number 
of  deaths  per  ioo  cases  or  as  the  number  of  cases  to  each  death. 
They  are  the  same  as  the  case  mortality  ratios  previously 
noted.  Owing  to  failures  to  report  all  cases  they  are  usually 
too  high  (Figs.  133,  134) 

For  areas  of  small  size  with  small  or  moderate  populations, 


STATISTICS    OF   SICKNESS 


327 


small  charts  will  enable  the  health  authorities  to  keep  in  touch 
with  the  daily  or  weekly  incidence  of  communicable  diseases 
and  detect  epidemics  in  their  incipiency.  On  the  other  hand, 
where  a  large  number  of  geographical  units  must  be  supervised 
a  more  rapid  method  of  ascertaining  fluctuations  of  disease 
prevalence  from  the  normal  or  endemic  prevalence  is  afforded 
by  comparison  of  the  monthly  summaries  with  the  so-called 
endemic  index  of  a  disease  for  the  area  under  consideration. 
This  is  the  average  monthly  incidence  of  the  reported  cases  of 
the  disease  in  a  given  geographical  unit,  exclusive  of  cases  rising 


1885 

1890 

1895 

1900 

190S 

1910 

) 

fc 

So 

" 

/ 

- 

/ 

/ 

/ 

15 

1 

- 

10 

. 

— 

1 

-. 

•f 

, 

Fig.   134. — Diphtheria — Fatality  rate  (number  of  deaths  registered  per  annum)  per- 
100  notified  cases) — Michigan — 1884  to  1910  (Trask,  Suppl.  12.,  P.  H.  Rep.). 

in  epidemics.  Such  standards  of  course  require  occasional 
revision.  By  their  employment  the  beginning  of  an  epidemic 
can  be  promptly  noted. 

REFERENCES 

Public  Health  Administration:  Its  Dependence  Upon   Reports  of  Cases  of 

Sickness.     Reprint  109,  Public  Health  Reports. 
A  Model   State  Law  for   Morbidity  Reports.     Reprint    133,  Public  Health 

Reports. 
Morbidity  Reports:   Their   Importance  to  the  Local  Health  Officer  and  His 

Work.     Reprint  153,  Public  Health  Reports. 
The  Massachusetts  Endemic  Index.     Reprint  442,  Public  Health  Reports. 
Industrial  Morbidity  Statistics.     Reprint  484,  Public  Health  Reports. 


SECTION  VIII 
PUBLIC  HEALTH 

CHAPTER  XXXVIII 
PUBLIC  HEALTH  ADMINISTRATION 

Public  health  administration  in  the  United  States  is  a  func- 
tion of  the  federal,  state  and  local  governments. 

THE  FEDERAL  AGENCIES  IN  PUBLIC  HEALTH  WORK 

The  principal  agency  in  this  field  is  the  Bureau  of  the 
Public  Health  Service  of  the  Treasury  Department,  which  has 
developed  out  of  the  old  Marine  Hospital  Service.  Other 
bureaus  whose  activities  are  related  to  public  health  are  the 
following : 

(a)  Census  Bureau,  Department  of  Commerce.  The  Cen- 
sus; Statistics  of  Births  and  Deaths. 

(b)  Children's  Bureau,  Department  of  Labor.  Child  Hygi- 
ene and  Maternal  Hygiene. 

(c)  Bureau  of  Animal  Industry,  Department  of  Agriculture. 
Federal  Meat  Inspection. 

(d)  Bureau  of  Chemistry,  Department  of  Agriculture.  Food 
Inspection. 

(e)  Bureau  of  Biological  Survey,  Department  of  Agriculture. 
Coyote  eradication  (rabies). 

(/)  Department  of  Labor.     Industrial  Hygiene. 

(g)  Bureau  of  Mines,  Department  of  Interior.  Industrial 
Hygiene  in  the  mining  industries. 

(h)  Bureau  of  Education,  Department  of  the  Interior. 
School  hygiene  and  sanitation. 

The  activities  of  the  Public  Health  Service  are  more  diverse, 
including  control  over  interstate  and  international  quarantine, 
supervision  of  the  manufacture  of  biological  products  for  hu- 
man use,  and  inspection  of  immigrants.  It  also  co-operates 
with  States  and  Local  Governments  in  epidemic  control  upon 
the  invitation  of  the  latter,  and  undertakes  demonstrations  of 

328 


PUBLIC   HEALTH    ADMINISTRATION 


329 


practical  sanitation,  and  conducts  field  and  laboratory  inves- 
tigation into  the  public  health  problems  of  the  United  States. 
It  can  thus  be  seen  that  there  has  been  no  systematic  or  co- 
ordinated plan  in  the  development  of  our  federal  public  health 
work.  Effective  work  is  being  done,  but  there  is  much  over- 
lapping; departmental  rivalry  cannot  stimulate  economical  or 
efficient  work.  There  is  great  need  for  a  co-ordination  of  all 
existing  federal  agencies,  which  probably  can  best  be  accom- 
plished by  their  segregation  into  a  single  Public  Health 
Department.     Lack  of  more  definite  federal  control  is  due  to 


FlG-     135- — A  muster  of  steerage  passengers.     The  boarding  launch  standing  by 
ready  for  orders.       (Cofer,  U.  S.  P.  H.  S.) 

the  fact  that  all  authority  that  the  federal  government  possesses 
has  been  delegated  by  the  individual  states.  The  present  trend 
of  national  policies  seems  to  be  towards  a  stronger  central 
government.  Where  this  will  end,  or  what  public  health  ac- 
complishments will  results  cannot  be  accurately  forecasted. 

Before  going  further  it  might  be  well  to  briefly  speak  of  the 
administration  of  maritime  quarantine.  All  vessels  either 
domestic  or  foreign  which  contemplate  touching  at  an  American 
port  from  abroad,  are  required  to  secure  from  the  American 
Consul  a  document  known  as  a  bill  of  health.  This  is  a  state- 
ment of  the  health  conditions  aboard  ship  during  her  stay  in 


330  PRACTICAL  PREVENTIVE   MEDICINE 

foreign  ports,  the  number  of  passengers  discharged,  embarked, 
etc.  Upon  her  arrival  at  an  American  port,  the  vessel  first 
drops  anchor  at  the  quarantine  station,  where  the  boarding 
officer  of  the  public  health  service  receives  the  Bill  of  Health 
and  examines  the  passengers,  crew  and  vessel  (Fig.  135).  If 
no  quarantinable  diseases  are  found  on  board  and  the  vessel 
has  not  come  from  a  plague  or  yellow  fever  port,  the  boarding 
officer  discharges  the  vessel  from  quarantine  by  the  issuance  of 
a  certificate  known  as  pratique.  She  is  then  free  to  proceed  to 
her  designated  wharf  or  moorings.  On  the  other  hand,  if  any 
of  the  quarantinable  diseases  (cholera,  yellow  fever,  plague, 
typhus,  small-pox  or  leprosy)  are  found  the  passengers  and  crew 
are  detained  in  quarantine  for  the  period  designated  in  the  regu- 
lations, while  their  baggage  and  effects  are  fumigated.  If  the 
vessel  comes  from  a  plague  or  yellow  fever  port,  the  vessel  is 
fumigated  with  sulphur  dioxide  or  hydrocyanic  acid  to  kill 
mosquitoes  or  rats.  After  these  requirements  are  met  pratique 
is  granted. 

STATE  PUBLIC  HEALTH  ADMINISTRATION 

Efficiency  of  organization  and  administration  varies  in  differ- 
ent states,  depending  on  their  degree  of  progressiveness,  freedom 
from  political  interference  and  the  appropriations  available.  In 
Massachusetts,  New  York,  Minnesota  and  a  few  others  the 
organizations  are  highly  efficient  and  developed  along  modern 
lines.  In  a  few  the  state  organizations  practically  exist  on 
paper.  The  organizations  in  the  remainder  are  manifestly 
inadequate.  In  these  the  state  organization  has  evidently  been 
particularly  designed  to  exercise  a  loose  supervision  over,  or  an 
advisory  capacity  toward  the  local  authorities,  without  possess- 
ing organization,  staff,  authority  or  appropriation  enough  to 
make  the  work  efficient. 

The  different  states  really  possess  broad  authority  in  matters 
pertaining  to  the  public  health  under  their  constitutional  police 
powers.  A  great  impediment  to  the  application  of  modern 
health  methods  is  the  fact  that  existing  legislation  is  fre- 
quently based  upon  antiquated  and  erroneous  ideas  of  pre- 
ventable diseases  and  hence  is  of  little  value. 

The  administration  of  existing  statutes  in  the  different  states 
is  accomplished  through  the  agency  of  State  Boards  or  Depart- 
ments of  Health.  In  the  former  authority  is  centered  in  the 
Board  and  affairs  move  slowly.     In  the  latter  the  head  of  the 


PUBLIC    HEALTH    ADMINISTRATION  33 1 

department  possesses  the  executive  authority  and  prompt  action 
is  possible.  An  unfortunate  phase  of  this  situation  is  the  fact 
that  many  of  the  appointments  to  these  executive  positions 
are  not  based  upon  training,  experience,  or  other  qualifications 
for  public  health  work,  but  are  given  as  rewards  for  political 
service.  There  is  much  opportunity  for  improvement  in  state 
health  administration  over  the  United  States. 

LOCAL  HEALTH  ADMINISTRATION 

The  units  of  local  administration  vary  in  different  states, 
from  counties  to  townships,  cities  and  towns,  the  latter  opera- 
ting upon  their  charter  authorizations.  Authority  is  usually 
vested  in  a  board  of  health,  whose  composition  may  be  either 
of  laymen  or  physicians,  either  elected  or  appointed.  Their 
authority  is  delegated  from  the  state.  In  operation  it  is  usual 
to  find  that  the  administration  of  these  local  units  is  inefficient 
as  well  as  inadequate.  Consequently  definite  policies  for  the 
improvement  of  the  public  health  or  local  sanitation  based  upon 
actual  local  needs  are  not  formulated,  and  little  or  nothing  is 
done  to  eradicate  or  reduce  the  preventable  diseases  of  local 
importance.  This  difficulty  is  usually  due  to  a  popular  apathy 
arising  through  ignorance  of  the  importance  of  health  matters 
and  what  may  be  done  to  remedy  the  evils.  Consequently  the 
local  health  administration  is  frequently  in  the  hands  of  incom- 
petent laymen  or  part  time  physicians,  whose  only  qualifications 
are  based  upon  proper  political  affiliations.  At  present,  de- 
fective local  health  organization  and  administration  is  the 
weakest  spot  in  public  health  protection. 

The  following  may  be  suggested  as  remedies  for  this  state  of 
affairs : 

(a)  Popular  education,  i.e.,  public  health  propaganda. 
Despite  such  efforts  the  public  conscience  can  sometimes  only 
be  stimulated  to  the  point  where  improvement  is  demanded  as  a 
result  of  a  disastrous  epidemic. 

(b)  Whole  time  public  health  officials  with  special  pro- 
fessional or  technical  qualifications  for  the  work.  Success  in 
this  field  requires  the  possession  of  an  abundance  of  tact  and 
diplomacy.  Properly  qualified  whole  time  men  should  receive 
adequate  remuneration. 

(c)  Adequate  ordinance  or  regulations  wisely  and  effectively 
enforced. 


332  PRACTICAL   PREVENTIVE    MEDICINE 

HEALTH  OFFICERS 

Health  officers  are  usually  the  executive  officers  of  the  local 
board  of  health,  whose  duty  it  is  to  enforce  the  existing ,  local 
regulations.  Most  commonly  we  find  they  have  been  recruited 
from  the  ranks  of  the  local  medical  profession  and  give  part 
time  service.  Their  tenure  of  office  is  usually  brief  and  their 
remuneration  likewise  slender.  Public  health  work  is  now  a 
distinct  field,  requiring  special  professional  training.  Medical 
training  is  of  distinct  value  for  public  health  work,  probably 
more  than  that  of  any  other  profession  if  considered  alone,  but 
we  must  recognize  that  in  itself  it  does  not  adequately  qualify 
an  individual  for  this  field  of  work. 

An  appreciation  of  the  importance  of  public  health  work  is 
is  rapidly  spreading  in  the  United  States  to-day-.  As  a  conse- 
quence we  shall  rapidly  see  the  old  order  of  incompetency  we 
have  sketched  pass  away.  The  new  order  will  demand  im- 
provement and  require  trained  men  to  direct  the  work.  Un- 
usual opportunities  now  present  themselves  to  trained  men  in 
this  field. 

HEALTH  LAWS  AND  REGULATIONS 

Drafts  of  proposed  health  legislation  had  best  be  carefully 
scanned  by  competent  lawyers  before  enactment.  Only  laws 
that  are  capable  of  enforcement  and  whose  constitutionality 
is  above  attack  are  of  value.  They  must  not  exceed  in  their 
scope  the  authority  delegated  by  the  state  to  local  administra- 
tive units.  It  must  also  be  recognized  that  ability  to  secure 
their  successful  enforcement,  particularly  in  those  cases  which 
require  jury  trials,  depends  upon  the  existence  of  a  popular 
sentiment  appreciating  their  necessity.  Proper  enacting  and 
penalizing  clauses  should  not  be  overlooked. 

NUISANCES 

Nuisances  are  what  the  name  implies,  both  to  the  laymen  and 
the  health  officer.  Most  conditions  belonging  to  this  category 
are  not  of  public  health  importance,  but  a  health  officer  may 
be  bothered  and  annoyed  by  questions  properly  referable  to 
police  and  peace  officers  for  solution  or  abatement.  From  a 
public  health  standpoint  the  chief  nuisances  are  grouped  as 
follows:  conditions  favoring  mosquito  breeding  (ponds, ditches, 
swamps,  etc.,)  rat  harbourage  (dumps,  dilapidated  buildings); 
fly   breeding   (manure  piles,  garbage);    and    excreta    disposal 


PUBLIC    HEALTH    ADMINISTRATION  333 

(dilapidated  privies,  full  vaults  etc.)  From  the  standpoint  of 
the  public  anything  which  is  offensive  to  the  senses  constitutes 
a  nuisance  and  many  are  the  basis  of  legislation.  A  better 
definition  is  "The  use  of  one's  property  in  such  a  way  as  to 
injure  the  rights  of  others  or  to  inflict  damages."  The  abate- 
ment of  nuisances  may  be  accomplished  through  four  different 
lines  of  procedure: 

(a)  by  criminal  action,  (b)  by  injunction,  (c)  by  suits  for 
damages  (private  suit)  and  (d)  by  abatement  under  statutory 
powers. 

PHYSICIAN'S  DUTIES  IN  PUBLIC  HEALTH  WORK 

^  A  physician's  responsibilities  in  public  health  work  are  of  two 
kinds,  his  professional  obligations  which  include  the  relationship 
between  himself  and  his  patients,  and  second,  his  legal  obliga- 
tions through  responsibilities  conferred  by  law. 

^  The  first  group  particularly  includes  the  following  responsi- 
bilities : 

(a)  Prompt  and  accurate  diagnosis. 

(b)  Efficient  treatment. 

(c)  Education  of  the  patient  and  his  family  in  simple  hygiene 
and  sanitation,  and  the  enlistment  of  their  co-operation  in  the 
cheerful  and  careful  discharge  of  measures  to  prevent  the  further 
spread  of  a  disease. 

(d)  Co-operation  with  the  legal  heaith  authorities. 
His  legal  obligations  include: 

(a)  Birth  registration. 

(b)  Signing  death  certificates. 

(c)  Morbidity  reporting. 

PUBLIC  HEALTH  EDUCATION 

Statutory  enactments  in  the  field  of  public  health  are  not  a 
panacea.  Their  purpose  should  be  to  secure  uniformity  of 
procedure,  to  provide  means  of  coercing  those  who  persist  in 
trespassing  on  the  rights  of  others  and  to  centralize  and  define 
authority.  Popular  support  is  only  given  as  the  people  see 
the  necessity  for  protection  and  feel  that  the  results  desired 
can  be  secured. 

Much  more  can  be  accomplished  by  the  education  of  the 
public  in  matters  of  hygiene  and  sanitation,  which  will  render 
compulsory  enforcement  unnecessary.  It  is  a  slow  process  and 
must  be  carefully  developed.     Avenues  of  instruction  available 


334  PRACTICAL   PREVENTIVE    MEDICINE 

are  through  the  press,  the  movies,  pamphlets  and  circulars, 
lectures,  special  conferences  and  exhibits,  and  instruction  in 
secondary  schools.  All  information  imparted  should  be  funda- 
mentally sound  and  one  should  avoid  making  dogmatic  state- 
ments about  debated  points  or  unsettled  questions.  It  is 
better  to  proceed  slowly  and  safely  than  to  later  find  it  neces- 
sary to  retract  statements.  Of  the  printed  channels  of  com- 
munication the  press  is  probably  the  best,  since  a  large  audience 
is  reached.  Articles  for  this  purpose  should  be  brief,  to  the 
point  and  written  in  simple  language.  Effective  publicity  work 
is  quite  an  art  and  should  receive  considerable  care  and 
attention. 

In  the  past  the  field  of  public  health  has  been  chiefly  charac- 
terized by  the  growth  and  developement  of  the  principles  of 
sanitation,  i.e.,  of  the  care  and  attention  that  must  be  expended 
upon  the  environment  of  the  human  race.  The  greatest 
achievements  have  been  realized  in  the  control  of  the  excreta 
and  insect  borne  infective  agents  in  those  communities  where 
their  application  has  been  undertaken.  One  is  probably  not 
greatly  in  error  in  declaring  that  in  those  communities  the  culti- 
vation of  this  field  has  very  nearly  yielded  its  maximum  fruitage. 
By  this  we  do  not  intimate  that  a  decline  in  the  rated  value  or 
esteem  of  sanitation  is  to  be  expected,  but  that  the  diseases 
which  may  be  considered  at  present  to  be  a  more  or  less  un- 
solved problem  in  preventive  medicine  will  be  conquered  by 
achievements  in  the  field  of  personal  hygiene.  Needless  to 
say  the  cultivation  of  this  field  may  not  be  expected  to  yield  as 
early  a  harvest  as  has  sanitation.  An  enlightened  policy  on  the 
part  of  public  health  officials,  together  with  administration 
by  trained  sanitarians,  in  other  words  the  activities  of  a  few 
individuals,  can  secure  all  the  benefits  arHng  from  adequate 
sanitation  to  a  community,  without  the  very  active  co-opera- 
tion of  the  individual  citizen.  On  the  other  hand,  personal 
hygiene  can  only  be  effectively  promoted  through  the  aroused 
interest  and  education  of  each  individual  in  the  entire  popula- 
tion concerned.  This  stage  will  arrive  slowly  and  it  may  require 
the  span  of  one  or  two  generations  before  hygiene  attains  the 
position  occupied  by  sanitation  at  the  present  time. 

PHILANTHROPIC  AGENCIES 

An  account  of  public  health  administration  would  not  be 
complete  without  calling  attention  to  the  assistance  given  by 
private  munificence.     One  of  the  most  notable  examples  is  that 


PUBLIC  HEALTH   ADMINISTRATION  335 

offered  by  the  Rockerfeller  Foundation  through  the  Inter- 
national Health  Board.  This  organization  is  made  possible 
by  the  income  from  funds  provided  by  John  D.  Rockefeller 
and  its  work  was  originally  directed  at  the  world  wide  control  of 
hookworm  disease.  This  has  later  been  extended  to  yellow 
fever  and  will  probably  later  include  malaria.  This  organiza- 
tion has  not  entered  the  field  independently.  Thus  in  the 
Southern  United  States  it  has  co-operated  with  the  different 
state  boards  of  health,  furnishing  competent  directors  and  a 
quota  of  the  funds.  The  results  that  are  following  this  work  are 
of  inestimable  value.  Another  philanthropy  working  along 
somewhat  different  lines  is  the  Russell  Sage  Foundation. 
PUBLIC  HEALTH  NURSING 

Successful  work  in  disease  control  and  prevention  largely 
depends  upon  the  degree  of  attention  paid  the  individual  human 
units  of  an  area.  The  realization  of  this  responsibility  pri- 
marily arose  in  the  out-clinic  departments  of  some  of  the  larger 
eastern  hopitals.  It  was  long  realized  that  many  patients 
ceased  attendance  at  the  clinics  before  being  fully  benefited  by 
their  treatment,  or  that  bed  patients  following  their  discharge 
in  a  condition  of  distinct  improvement,  returned  to  home  sur- 
roundings so  unfavorable  that  the  improvement  laboriously 
achieved  by  the  hospital  was  soon  lost.  Efforts  were  made  to 
improve  these  conditions  through  the  frequent  visitation  of 
patients  in  their  homes,  by  urging  the  continuation  of  their 
clinic  attendance,  by  instructing  the  responsible  members  of 
the  family  in  their  proper  feeding  and  care,  by  providing  the 
assistance  of  charitable  agencies  where  such  assistance  was 
required.  As  a  consequence  the  benefits  of  the  hospitals  have 
been  greatly  extended  and  their  accomplishments  afforded  a 
greater  degree  of  permanency.  This  type  of  service  has  been 
adopted  by  various  health  departments,  for  the  most  part  se- 
curing the  services  of  graduate  nurses  for  this  purpose.  We 
have  previously  called  attention  to  public  health  nursing  in 
connection  with  maternity  and  child  welfare  clinics.  A  similar 
service  can  be  rendered  in  the  control  of  communicable  diseases, 
through  proper  follow  up  care  of  patients  discharged  from  isola- 
tion. Another  variation  of  this  type  of  service  is  afforded  by 
the  so-called  visiting  nurse,  who  makes  periodical  visits  to  the 
homes  of  those  unable  to  provide  hospital  facilities  or  trained 
nursing,  or  where  free  hospital  beds  are  not  available,  re- 
gardless of  the  character  of  the  patient's  illness.     Instruction 


336  PRACTICAL   PREVENTIVE    MEDICINE 

is  given  the  responsible  members  of  the  household  in  the  proper 
feeding  and  care  of  the  patient  and  in  the  execution  of  the 
physician's  directions.  The  daily  visits  are  continued  as  long 
as  necessary  to  insure  a  continuation  of  the  lessons  given  and 
to  give  further  instruction.  Thus  in  the  public  health  nurse 
there  has  developed  a  distinct  type  in  the  social  worker. 

REFERENCES 

Maritime  Quarantine.     Public  Health  Bulletin  34,  U.S.P.H.S. 

Chapin:  A   report    on    State    Public   Health   Work   based  on  a  Survey  of 

State  Boards  of  Health.     American  Medical  Association. 
Interstate  Quarantine  Regulations  of  the  United  States.     U.S.P.H.S. 
What     Social   Workers    Should    Know    About    Their    Own    Communities. 

Pub.  7,  Russel  Sage  Foundation. 
Hemenway:  Legal  Aspects  of  Public  Administration. 
Gardner:  Public  Health  Nursing. 
State   and  Insular  Health   Authorities,    1918.      Reprint  488,  Public  Health 

Reports. 
Public  Health   Administration   in  Minnesota.     Reprint    233,  Public  Health 

Reports. 
Cooperative    Public    Health    Administraton.     Reprint    222,    Public   Health 

Reports. 
Federal     Public     Health     Administration.     Reprint     112,     Public    Health 

Reports. 
The  Practicing   Physician:  His   Relation   to   Public  Health  Administration. 

Reprint  280   Public  Health  Reports. 
Directory    of    City    Health    Officers,    191 7.    Reprint    416,    Public    Health 

Reports. 
Public    Health    Laboratory    Specimens,    their    preparation    and  shipment. 

Reprint  438,  Public  Health  Reports. 
Overton    and    Denno:   "The    Health    Officer."     Chapters,     I,    II,    III, 

IV,  VI,  VII,  VIII,  IX,  XI,  XII,  XXXVI. 


INDEX 


Accessory  food  factors,  233 
Accidents,   industrial,   factors  in  pro- 
duction, 244 
Activation      treatment      of      sewage, 

112 
Acute  gastro-enteritis  as  a   cause  of 
infant  mortality,  268 
infections  as  a  cause  of  infant  mor- 
tality, 269 
respirator}'-  infections  as  a  cause  of 
infant  mortality,  269 
Adenoids,  277 

Administration,  public  health,  federal, 
328 
local,  331 
state,  330 
Adulterations  of  food,  225 

of  milk,  150-225 
Aeration  of  water,  131 
Air,  amount  of,  necessary,  286 
bad  or  injurious,  283 
chemical  composition,  282 
cold,  damp,  284 


heating  and  ventilation,  283 

humidity  of,  283 

odors  in,  283 

pressure  as  an  occupational  hazard, 
242 

relation  of  man  to,  284 

variations  of,  282 

warm,  dry,  284 
moist,  284 
Albinism,  263 
Alcoholism,  234 
Alga?  in  water,  127 
Algal  destruction,  131 
Alummosis,  253 
Amoebic  dysentery,  70 
Animals  as  sources  of  infection,   203 

22  337 


Anopheline  mosquitoes,  188 
adult,  189 

resting,  190 
egg,  189 
larvae,  190 
pupEe,  190 
Anthrax,  communicability,  period  of, 
215 
disinfection  in,  215 
entrance  of,  215 
exit  of  infective  agent,  215 
general  measures  against,  215 
immunization  of  cattle,  215 

of  man,  215 
infective  agent  of,  215 
incubation  period  of,  215 
isolation,  215 
methods  of  control,  215 
occupational,  216 
quarantine,  215 
route  of  transmission,  215 
source  of  infection,  215 
Anthracosis,  253 

Antitoxin,  diphtheria,  employment  of, 
60 
tetanus,  employment  of,  218 
Arithmetical    method    of    population 

estimation,  304 
Arsenic  as  an  industrial  poison,  249- 

250 
Artificial  feeding  of  infants,  271 
Aseptic  nursing,  technique  of,  77 
Aspiration  in  ventilation,  286 
Aural  hygiene,  276 

Bacteria  in  milk,  sources  of,  150 

in  certified  milk,  158 

in  inspected  milk,  160 

in  water,  128 
Bacterial  standards  for  water,  128 


33* 


INDEX 


Bathing,  hygiene  of,  292 

Baths,  kinds  of,  293 

Bed-bug,  199-201 

Bends,  242 

Benzin  as   an  industrial  poison,  249- 

251 
Benzol   as  an  industrial   poison,    249 
Beri-beri,  definition  of,  230 

distribution,  230 

etiology  of:  past  ideas,  231 
present  ideas,  231 

incidence  of,  231 

prevention  of,  233 

public  protection,  234 
Bills  of  health,  329 
Biological    transmission    of    infective 

agents  by  insects,  1S0 
Birth,  accidents  at,  as  a  cause  of  in- 
fant mortality,  267 

certificate,  313 

rates,  312 

factors  influencing,  314 

records,  value  of,  312 

registration,  312 

statistics,  312 
Black  boards,  279 
Blindness,  preventable,  46 
Boarding  of  babies,  270 
Body  louse,  destruction  of,  187 
Boiling   as   a    means   of    disinfection, 

95-98 
Botulism,  178 

Brass  founders  ague,  251-252 
Breast  feeding,  271 
Breathing  cone,  286 

zone,  286 
Bubonic  plague,  203-205 
Burial  permits,  314 
Byssinosis,  253 

Canned  food,  178 

Carbon  bisulphid  as  an  insecticide,  187 

dioxid  of  the  atmosphere,  284 
Caries,  dental,  277 
Carriers,  26 

classification  of,  26 

convalescent,  examples  of,  28 


Carriers,  healthy,  examples  of,  27 

incubatory,  examples  of,  27 
Cases,  abortive,  26 

atypical,  26 
examples  of,  27 

latent,  27 

missed,  26 

typical,  26 
Cause  of  death,  statement  on  death 

certificate,  314 
Census,  301 

enumerations,  errors  in,  302 
Ceratophyllus  fasciatus,  204 
Cesspools,  120 

leaching,  122 

vaulted,  122 
Chalcicosis,  253 
Charities,  milk,  273 
Chemical  closets,  117 
Chicken-pox   communicability,  period 
of,  51 

entrance  of,  51 

exit  of  infection,  51 

incubation  period,  51 

infective  agent,  50 

methods  of  control,  5r 

route  of  transmission,  51 

source  of  infection,  51 
Childhood,  communicable  diseases  of, 

275 
definition  of,  275 
Children's    diseases   and    contact,    37 

hygiene  of,  275 
Chlorinated  lime  as  a  disinfectant,  98 
Chlorine  as  a  disinfectant   of   water, 

138-146 
in  water,  127 
Cholera,  Asiatic,  69 

communicability,  period  of,  69 

disinfection,  69 

entrance  of,  69 

epidemic  measures,  70 

exit  of  infective  agent,  69 

immunization,  artificial,  69 

incubation  period,  69 

infective  agent,  69 

isolation,  69 


INDEX 


339 


Cholera,  Asiatic,  methods  of  control,  69 
quarantine,  69 
routes  of  transmission,  69 
source  of  infection,  69 
Cimex  lectularius,  199,  201,  204 
Cistern,  protection  of,  145,  148 
Class-room,  cleaning  of,  280 
Cleanliness,    personal,    education    of 
public  in,  92 
facilities  for,  289 
Climate,  relation  of  clothing  to,   294 
Closet,  indoor,  298 
Clothing,  hygiene  of,  293 
Coagulation  in  treatment  of  water,  133 
Color  blindness,  264 

of  clothing,  294 
Common  personal  articles,  34 
Communicability,   period   of,   in    an- 
thrax, 215 
chicken-pox,  51 
cholera,  69 
dengue,  197 
diphtheria,  59 
dysentery,  amoebic,  71 

bacillary,  71 
german  measles,  54 
gonorrhoea,  43 
influenza,  57 
leprosy,  66 
malaria,  191 
measles,  51 
meningitis,  61 
mumps,  52 
plague,  63 
poliomyelitis,  63 
pneumonia,  63 
poliomyelitis,  63 
rabies,  212 
relapsing  fever,  200 
scarlet  fever,  55 
septic  sore  throat,  56 
small-pox,  48 

spotted  fever,  rocky  mt.,  210 
syphilis,  41 
tetanus,  217 
tuberculosis,  64 
typhoid,  67 


Communicability,   period    of,   typhus 
fever,  197 
uncinariasis,  72 
whooping  cough,  56 
yellow  fever,  196 
Communicable  diseases,  definition  of, 

24 
Confinements,  proportion  at  home  and 

at  hospital,  257 
Congenital   defects  as   a   cause  of  in- 
fant mortality,  267 
Conjunctivitis,  acute,  276 
Contact,  beds,  115 
direct,   diseases    transmitted    solely 
by,  34 
importance     of,     with     different 
infective  agents,  34 
definition  of,  ^3 
density  of  population  and,  36 
diseases  and  seasons,  39 

frequently     transmitted     by,    35 
usually  transmitted  by,  35 
effect  of  over-crowding  on,  37 
epidemics,  character  of,  39 
importance  of  with  different  types 

of  sources  of  infection,  36 
indirect,  34 
means  of,  ^^ 

route  of  exit  from  the  body  and,  35 

transmission,  features  characteristic 

of,  36 

Contagious  diseases,  definition  of,  24 

Cooked  food,  178 

Cotton,  value  as  a  fabric  for  clothing, 

294 
Cow-pox,  203 
Crede's    prophylaxis    for    ophthalmia 

neonatorum,  46 
Cyanide  as  an  insecticide,  186 

Dairy  inspection,  score  card  for,  161 
products  as  routes  of  infection,  163 
Deaf  mutism,  263 
Death  certificate,  314-315 
errors  in,  314 
rates,  317 

corrected,  320 


34° 


INDEX 


Death  rates,  factors  influencing,  321 
specific,  319 
standardized,  320 

records,  value  of,  315 
Defects,  orthopedic,  275 
Degenerate,  264 

De-limitation  of  plague  focus,  207 
De-lousing  equipment,  use  of,  199-200 
Demography,  definition  of,  301 
Dengue,   communicability,   period   of, 
197 

disinfection,  197 

entrance  of  infective  agent,  197 

exit  of  infective  agent,  197 

immunization,  197 

incubation  period  of,  197 

infective  agent,  196 

isolation,  197 

methods  of  control,  197 

quarantine,  197 

route  of  transmission,  197 

source  of  infection,  196 
Dental  hygiene,  277 
Dermacentor  venustus,  210-21 1 
Dessication  as  a  disinfectant,  95 
Determiner,  261 
Diet,  insufficient,  229 

representation  of  food  elements  in, 
224 

unbalanced,  229 
Digestion  tanks,  two  story,  no 
Diphtheria,  antitoxin,  administration 
of,  59 

communicability,  period  of,  59 

disinfection,  61 

entrance  of,  59 

exit  of  infective  agents,  59 

general  measures,  61 

immunization,  artificial,  59 

incubation  period,  59 

infective  agent,  59 

isolation,  59 

methods  of  control,  59 

quarantine,  61 

route  of  transmission,  59 

Schick  test,  60 

source  of  infection,  59 


Diptheria,  toxin-antitoxin  mixtures,  60 
Dirt  in  milk,  152 
Dipping  domestic  animals,  210 
Disease  control,  principles  of,  74' 
Diseases,  preventable,  classes  of,    17- 

18 
Dishes,  sterilization  of,  227 
Disinfectants,  action,  manner  of,  94 

chemical,  95 

definition  of,  94 

desiccation  as  a,  95 

efficiency  of,  97 

external,  94 

gases  as,  95 

heat  as  a,  95 

internal,  94 

light  as  a,  95 

physical,  94 

properties  of  an  ideal,  96 

solutions  as,  95 

standardization  of,  95 

suspension  as,  95 
Disinfection  concommittant,  79 

concurrent,  79 

definition  of,  94 

of  water,  138 

technique  of,  concurrent,  97 

terminal,  79 
Dogs,  muzzling  of,  214 
Domestic  excreta  disposal,  116 
results  of,  143 

sanitation,  295 

water  supplies,  145 

emergency  protection  of,  146 
Dominant  characteristics,  261 
Dosage  of  infective  agents,  30 
Drainage,  anti-mosquito,  191 

area  of  operations,  192 
Droplet  infection,  33 
Duplex  combinations  of  determiners, 

263 
Dusts  as  an  occupational  hazard,  238- 
252 

remedies  for,  253 
Dwellings,  construction  of,  245 

definition  of,  307 

location  of,  295 


INDEX 


341 


Dysentery,  amoebic,  communicability, 

period  of,  71 
disinfection,  71 
entrance  of,  71 
exit  of,  71 

general  measures,  71 
immunization,  artificial,  71 
incubation  period  of,  71 
infective  agent,  70 
isolation,  71 
methods  of  control,  71 
quarantine,  71 
route  of  transmission,  70 
source  of  infection,  70 
bacillary,    communicability,   period 

of,  71 
disinfection,  72 
entrance  of,  71 
exit  of,  71 

general  measures,  72 
immunization,  artificial,  71 
incubation  period  of,  71 
infective  agent,  71 
isolation,  71 
methods  of  control,  71 
quarantine,  72 
route  of  transmission,  71 
source  of  infection,  71 

Eating  houses,  227 

Education,     public     health,     of     the 

public,  333 
Electrical  hazards,  242 
Emmigration,  303 
Endemic,  definition  of,  25 

index,  327 
Enteric  group,  67 
Epidemic,  definition  of,  25 
Epidemics,  168 

contact,  39 

food  borne,  178 

milk  borne,  172,  173 

water  borne,  125 
Epidemiological  investigation,  86 
analysis  of  data,  91 
data  required,  86 
emergency  epidemiology,  92 


Epidemiological    investigation,     plot- 
ting of  cases,  91 

routine  epidemiology,  92 
Epidemiology,  definition  of,  24 
Epizootic,  definition  of,  25 
Eucalyptus,  192 
Eugenics,  265 

Excreta,  disposal,  domestic,  298 
modern  methods  of  disposal,  104 
relationship  to  health,  104 
Exercise,  effects  of,  289 

influence  of,  on  metabolism,  288 

on  arterial  pressure,  289 

on  digestive  processes,  289 

on  flow  of  blood  and  lymph,  288 

on  heart,  288 

on    heat    production    and    regu- 
lation, 289 

on  muscular  tissues,  289 

on  perspiration,  289 

on  respiration,  289 

on  slumber,  289 
Explosions,  mine,  241 
Explosives,  permissible,  241 
Eye  strain,  276 

Fatigue,  238-290 

effect  of  excitement  on,  291 

industrial,     relation     to     accidents, 
291 

muscle,  290 

neurone,  290 

receptor,  290 
Federal  agencies  in  public  health  work, 

328 
Feeble  mindedness,  264 
Feeding,  artificial,  of  infants,  271 

breast,  of  infants,  271 
Felix-Weil  reaction,  197 
Filling,  anti-mosquito,  191 
Filters,  rapid  sand,  136 

roughing,  112 

slow  sand,  135 

trickling,  115 
Filtration,   intermittent  sand,  of  sew- 
age, 115 

of  water,  135 


342 


INDEX 


Fingers  as  a  means  of  contact  transfer, 

33 
Fire  hazards,  242 

in  mining,  241 
Fish  as  an  anti-mosquito  agent,  192 
Fleas  as  a  vector,  204 

destruction  of,  205 
Focal  infection,  221 
Fo mites,  32 

distinction  from  indirect  contact,  32 
Food  handling,  hygiene  of,  227 

accessory  factors,  233 

adulteration  of,  225 

animal,  225 

as  a  route  of  infection,  175 

caloric  value  of,  223 

definition  of,  223 

determination  of  suitability,  223 

elementary,  223 

epidemics,  178 

origin  of,  225 

preservation  of,  226 

poisonous,  230 

proportion  of  elements  of,  in  daily 
diet,  224 

refrigeration  of,  in  the  kitchen,  300 

relation  to  health,  229 

requirements,  224 

production  and  retail,  223 

retail  of,  226 

use  by  body,  223 

utilization  of  elements  of,  in  daily 
diet,  224 

vegetable,  225 
Foot  and  mouth  disease,  167-203 
Formaldehyde  as  a  fumigant,  98 
Formalin,    solution     for     disinfection, 

97 
Fracastorius,  21 
Friedreich's  ataxia,  264 
Fumigants,  employment  of,  98 
Fumigation,  preparation  for,  95-102 
Fungi,  lower  animals  as  sources  of,  203 

Gambusia,  192 

Ganister  disease,  253 

Garbage,  disposal,  in  the  kitchen,  300 


Geometrical    method    of    population 

estimation,  305 
German      measles,      communicability 
period  of,  54 

disinfection,  54 

entrance  of,  54 

exit  of  infective  agent,  54 

incubation  period,  54 

infective  agent,  54 

isolation,  54 

methods  of  control,  54 

quarantine,  54 

route  of  transmission,  54 

source  of  infection,  203 
Glanders,  203 
Gonorrhoea    communicability,    period 

of,  43 
disinfection,  43 

entrance  of  infective  agent,  43 
exit  of  infective  agent,  42 
general  measures,  43 
immunization,  43 
incubation  period,  43 
infective  agent,  42 
isolation,  43 
methods  of  control,  43 
route  of  transmission,  42 
source  of  infection,  42 

Haffkine's  vaccine,  205 

Halls,  management  of  ventilation,  287 

Hands  as  a  means  of  contact  transfer, 

33 
Hardness  of  water,  127 

permanent,  127 

temporary,  127 
Hazards,  occupational,  classified,  236 
Health  officers,  332 
Hearing,  defective,  276 
Heat,  as  a  cause  of  infant  mortality, 

273 
as  a  disinfectant,  95 
excessive,  as  an  occupational  haz- 
ard, 238 
losses  from  the  body,  283 
Heating,     artificial,     bodily     require- 
ments, 285 


INDEX 


343 


Heating,  artificial,  means  for,  285 

domestic,  297 

of  schools,  279 
Hemophilia,  264 
Hereditary  diseases,  260 
Heredity,  definition  of,  260 
Hides,    as    a    route    of   infection    for 
anthrax,  215 

disinfection  of,  217 
Holmes,  O.  W.,  22-256 
Home  environment,  unsanitary,  237 
Hookworm  disease,  see  also  Uncinaria  ■ 

sis,  72 
House  fly  borne  epidemics,  184 

control  of,  185 
Humidity,  effect  on  the  bodily  comfort, 
283 

extremes  of,  238 
Huntington's  chorea,  263 
Hybrids,  261 

Hydrocyanic  acid  gas  as  an  insecti- 
cide, 186 
Hygiene,  definition  of,  17 

personal,  288 

Illumination,  296 

Imhoff  tanks,  no 

Immigration,  303 

Immunization,  artificial,  as  a  defensive 

weapon,  222 
in  prophylaxis  of  anthrax,  215 

of  chicken  pox,  51 

of  cholera,  69 

of  diphtheria,  59-60 

of  dysentery,  amoebic,  71 
bacillary,  71 

of  dengue,  197 

of  german  measles,  54 

of  gonorrhoea,  43 

of  influenza,  57 

of  leprosy,  66 

of  malaria,  191 

of  measles,  52 

of  meningitis,  62 

of  mumps,  53 

of  plague,  205 

of  pneumonia,  64 


Immunization,  artificial,  in  prophylaxis 
of  poliomyelitis,  63 

of  rabies,  212 

of  relapsing  fever,  200 

of  scarlet  fever,  55 

of  septic  sore  throat,  56 

of  small  pox,  49 

of  spotted  fever,  Rocky.  Mt,  210 

of  syphilis,  42 

of  tetanus,  217 

of  tuberculosis,  65 

of  typhoid,  68 

of  Uncinariasis,  73 

of  whooping  cough,  57 

of  yellow  fever,  196 
Inactivity,  238 

Incubation  period,  definition  of,  24 
extrinsic,  181 
in  anthrax,  215 
in  chicken  pox,  51 
in  cholera,  69 
in  diphtheria,  59 
in  dysentery,  amoebic,  71 

bacillary,  71 
in  dengue,  197 
in  german  measles,  51 
in  gonorrhoce,  43 
in  influenza,  57 
in  leprosy,  66 
in  malaria,  189 
in  measles,  51 
in  meningitis,  61 
in  mumps,  52 
in  plague,  204 
in  pneumonia,  63 
in  poliomyelitis,  62 
in  rabies,  212 
in  relapsing  fever,  199 
in  scarlet  fever,  55 
in  septic  sore  throat,  56 
in  small  pox,  48 

in  spotted  fever,  Rocky,  Mt.,  210 
in  syphilis,  41 
in  tetanus,  217 
in  tuberculosis,  64 
in  typhoid,  67 
in  typhus  fever,  197 


344 


INDEX 


Incubation  period,  in  uncinariasis,  72 
in  whooping  cough,  56 
in  yellow  fever,  195 
Infancy,  definition  of,  267 
hygiene  of,  267 
mortality  during,  267 
Infants,  institutional  care  of,  270 
mortality,  causes  of,  267 
as  a  sanitary  index,  270 
comparative,  268-269 
methods  of  expressing,  321 
Infections,  industrial,  239 
Infectious  disease,  definition  of,  24 
Infective  agents,  extra  corporeal  ex- 
istence of,  50 
portals  of  entrance,  30 
routes  of  exit  from  body,  28 
Influenza,  communicability,  period  of, 

57 

disinfection,  58 

entrance  of,  57 

exit  of  infective  agent,  57 

general  measures,  58 

immunization,  artificial,  57 

incubation  period,  57 

infective  agent,  57 

isolation,  57 

methods  of  control,  57 

routes  of  transmission,  57 

source  of  infection,  57 
Insecticides,  185 

carbon  bisulphid  as,  187 

hydrocyanic  acid  gas  as,  185 

physical  agencies,  187 

pyrethrum,  187 

sulphur  dioxid  as,  185 

use  of,  185 
Irrigation,  broad,  of  sewage,  115 

sub-surface  of  sewage,  114 
Isolation,    conditions    necessary    for, 

75 
definition  of,  74 
hospitals, 

cubicle  type,  76 

pavillion  type,  76 
success  of,  80 
termination  of,  80 


Jenner,  22 

Kircher,  22 

Kitchen,  sanitation  of,  299 

Koch,  Robert,  23 

Larvacide  of  Darling,  192 
Law,  public  health,  332 
Lead  poisoning,  channels  of  entrance, 
247 

from  water,  125 

industries  in  which  encountered, 

245 
remedies,  249 
symptomatology,  249 
Leeuwenhoek,  van,  22 
Leprosy  communicability,  period  of,  66 

disinfection,  66 

exit  of  infective  agent,  65 

general  measures,  66 

incubation  period,  66 

infective  agent,  66 

isolation,  66 

methods  of  control,  66 

routes  of  transmission,  66 

source  of  infection,  65 
Leptospira  icteroides,  195 
Light  as  a  disinfectant,  95 
Lighting  as  an  occupational  hazard,  237 

of  dwellings,  296 

of  schools,  278 
Lime,  chlorinated,   solution  for  disin- 
fection, 98 

unslaked,    solution  for  disinfection, 
98 
Liquor    cresolis    compositus,     solution 

for  disinfection,  98 
Local  public  health  administration,  311 
Loemopsylla  cheopis,  204 

Machinery  as  an  occupational  haz- 
ard, 240 
guarding  of,  240 
Malaria,  communicability,  period  of, 
191 
control  in  rural  areas,  195 
disinfection,  191 


INDEX 


345 


Malaria,  effect  of  temperature,  on  par- 
asites in  insects,  181 

entrance  of  infective  agent,  188 

exit  of  infective  agent,  188 

general  measures,  191 

immunization,  191 

incubation  period,  189 

infective  agents  of,  188 

isolation,  191 

methods  of  control,  189 

mosquito  control,  191 

quarantine,  191 

quinine  prophylaxis,  191 

route  of  transmission,  188 

source  of  infection,  188 

sterilization  of  gamete  carriers,  191 
Malta  fever,  168,  203 
Manson,  Patrick,  22 
Manure  in  milk,  152 
Maritime  quarantine,  329 
Masks,  78 

Maternity  clinics,  258 
Measles  communicability,  period  of,  51 

disinfection,  52 

entrance  of,  51 

exit  of  infective  agent,  51 

general  measures,  52 

infective  agent,  51 

incubation  period,  51 

isolation,  52 

methods  of  control,  52 

quarantine,  52 

route  of  transmission,  51 

source  of  infection,  51 
Meat,  animal  parasitism  of,  176 

diseases  transmitted  by,  176 

inspection  of,  175 

poisoning,  176 

unsuited  for  food,  175 
Mechanical   transmission  of  infective 

agents  by  insects,  182 
Mendelian  inheritance,  260 

ratio,  261 
Meningitis,    meningococcic,    (cerebro- 
spinal),     communicability, 
period  of,  61 
disinfection,  62 


Meningitis,    meningococcic,    entrance 
of,  61 

exit  of  infective  agent,  61 

general  measures,  62 

immunization,  62 

incubation  period,  61 

infective  agent,  61 

isolation,  62 

methods  of  control,  62 

quarantine,  62 

routes  of  transmission,  61 

source  of  infection,  61 
Mercury  as  an  industrial  poison,  249 
Methods  of  control  of  anthrax,  215 
of  chicken  pox,  51 
of  cholera,  69 
of  dengue,  197 
of  diphtheria,  59 
of  dysentery  amoebic,  71 

bacillary,  71 
of  german  measles,  54 
of  gonorrhoea,  43 
of  influenza,  57 
of  leprosy,  66 
of  malaria,  191 
of  measles,  52 
of  meningitis,  62 
of  mumps,  52 
of  plague,  205 
of  pneumonia,  63 
of  poliomyelitis,  63 
of  rabies,  212 
of  relapsing  fever,  200 
of  scarlet  fever,  55 
of  septic  sore  throat,  56 
of  small  pox,  48 

of  spotted  fever,  Rocky.  Mt.,  210 
of  syphilis,  41 
of  tetanus,  217 
of  tuberculosis,  65 
of  typhoid,  67 
of  typhus  fever,  197 
of  uncinariasis,  73 
of  whooping  cough,  57 
of  yellow  fever,  196 
Micro-organisms,  portals  of  entrance,  29 
route  of  exit  from  body,  28 


346 


INDEX 


Midwives,  relation  to  puerperal  septi- 
cemia, 257 
Mining    and    quarrying,    hazards    of, 

241 
Milk,  as  food,  149 

as  route  of  infection,  167 

care  of,  in  the  home,  165 

certified,  157 

classification  of,  153-157 

development    of    pathogenic     bac- 
teria, 168- 171 

dirt,  gross,  in,  152 

for  infant  feeding,  271 

germicidal  property  of,  167 

inspected,  160 

market,  r6o 

micro-organisms  in,  150 

pasteurization  of,  154 

raw  milk,  153 

relationship   to   health  and  disease, 

149 
source   of  pathogenic  organisms  in, 

167-171 
sophistication  of,  150 
sources  of,  151 
production  of,  151 
temperature  of  storage,  153 
with  relation  to  anthrax,  216 
Milking  utensils,  152 
Mills-Reincke  phenomenon,  144 
Minnow,  top,  192 
Model  morbidity  law,  323 
Montague,  Lady  Mary  Wortley,  22 
Morbidity  rates,  326 

reporting,   checks   on   completeness 
of,  325 
physicians  duties  in,  83 
reciprocal  notification,  85 
reportable  diseases,  list  of,  84 
requirements    for    reporting,  84- 

323 
reports,   use  of,   by  health  authori- 
ties, 325 
statistics,  323 
Mortality     statistics,     314,     see    also 

Deaths,  314 
Mosaic  law,  21 


Mosquitoes,     destruction     of     adults, 
194 
of  breeding  places,  191-196 
oflarvas,  192 

exclusion  of  adults,  194 

in  dengue,  197 

in  malaria,  188 

in  yellow  fever,  196 
Mouth  spray,  33 

Mumps,   communicability,    period  of, 
52 

disinfection,  53 

entrance  of  infective  agent,  52 

exit  of  infective  agent,  52 

incubation  period,  52 

infective  agent,  52 

isolation,  52 

methods  of  control,  52 

quarantine,  53 

route  of  transmission,  52 

source  of  infection,  52 
Muzzling  of  dogs,  214 

Natural  immunity,  265 

Negri  bodies,  212 

Nitrogenous  compounds  in  water,  127 

Nose,  hygiene  of,  277 

Notification,  323 

Nuisances,  332 

Nurses,  visiting,  273 

Nursing,  public  health,  335 

Nutritional  deficiencies,  277 

disturbances   as   a   cause   of  infant 
mortality,  268 

Obstetrical   care  for  rural   women, 

259 
Occupational     anthrax,     control      of, 
216 

hazards,  classified,  236 
Ocular  hygiene,  276 
Odors,  as  a  cause  of  bad  air,  283 
Oiling  as  an  anti-mosquito  measure, 

192 
Ophthalmia  neonatorum,  46 

Crede's  prophylaxis  of,  46 
Orthopedic  defects,  275 


INDEX 


347 


Ova,  destruction  of  helminth,  98 
Overcrowding  of  dwellings,  297 
Oxygen,  dissolved  in  water,  107 
Oysters,  176 

Pandemic,  definition  of,  25 
Paratyphoid  fever,  67 
Pasteur,  Louis,  22 
Pasteur  treatment,  213 
Pasteurization  of  milk,  against  milk- 
borne  tuberculosis,  170 
effects  of,  155 

on  typhoid,  171 
flash  method,  154 
holding  method,  154 
in-bottle  method,  155 
in  the  home,  165 
storage  of,  157 
temperature  of,  155-160 
time  of,  155-160 
Pediculus  vestimenti,  197-198 
Pellagra,  definition  of,  230 
distribution  of,  230 
etiology  of:  past  ideas,  231 

present  ideas,  231 
incidence  of,  231 
prevention  of,  233 
public  protection,  234 
Perflation  in  ventilation,  286 
Personal  hygiene,  288 
Phenol    solution    for   disinfection,    98 
Philanthropic  agencies,  334 
Plague  communicability,  period  of,  204 
disinfection,  205 
entrance  of  infective  agent,  204 
exit  of  infective  agent,  204 
general  measures,  205 
immunization,  artificial,  205 
incubation  period,  204 
infective  agent,  203 
isolation,  205 
methods  of  control,  205 
quarantine,  205 
route  of  transmission,  204 
source  of  infection,  203 
Plenciz,  22 
Plenum  system  of  ventilation,  286 


Pneumonia,    acute    lobar,    communi- 
cability, period  of,  63 
disinfection,  64 

entrance  of  infective  agent,  63 
exit  of  infective  agent,  63 
general  measures,  64 
immunization,  artificial,  64 
incubation  period,  63 
infective  agent,  63 
isolation,  64 
methods  of  control,  63 
quarantine,  64 
route  of  transmission,  63 
source  of  infection,  63 
Pneumonic  plague,  203-205 
Pneumonokoniosis,  252 
Poisons,  industrial,  238 
Poliomyelitis,  communicability,  period 
of,  63 
disinfection,  63 

entrance  of  infective  agent,  63 
exit  of  infective  agent,  63 
general  measures,  63 
immunization,  63 
incubation  period,  63 
infective  agent,  63 
isolation,  63 
methods  of  control,  63 
quarantine,  63 
routes  of  transmission,  63 
source  of  infection,  63 
Population,  density  of,  308 
estimation  of,  304 
fluctuations  of,  303-309 
relation  of,  to  vital  statistics,  301 
Pratique,  330 
Precipitation,     chemical,     in     sewage 

treatment,  no 
Prematurity  as  a  cause  of  infant  mor- 
tality, 267 
Prenatal  clinics,  272-258 
Preservatives,  food,  225-226 
Preventable  diseases,  losses  from,    18 
Preventive  medicine,  curative  aspect, 
20 
definition  of ,  17 
development  of,  21 


348 


INDEX 


Preventive      medicine,      prophylactic 
aspect,  20 
results  from  application  of,  19 
Primary  case,  definition  of,  24 
Privies,  298 
leaching,  119 
pail  or  can,  119 

requirements  for  satisfactory,  117 
vaulted,  119 
Prostitution,   relationship  to    alcohol- 
ism, 234 
to  venereal  diseases,  41 
Public  health  administration,  328 
nursing,  335 
physician's  duties  in,  333 
scope  of  work,  21 
service,  U.  S.,  328 
Puerperal  septicemia,  256 

state,  diseases  arising  from,  255 
deaths  during,  255 
Pure  food  legislation,  225 
Purification  of  water,  131 
results  of,  143 
selection  of  process,  144 
self,  of  streams,  107 
Pus  pockets,  dental,  277 
Pyorrhoea,  277 

Quarantinable  diseases,  list  of  (fed- 
eral), 330 

Quarantine,  definition  of,  74 
maritime,  329 

Rabies    communicability,    period    of, 
212 
disinfection,  214 
entrance  of,  212 
exit  of  infective  agent,  212 
general  measures,  214 
immunization,  212 
incubation  period,  212 
infective  agent,  212 
isolation,  212 
methods  of  control,  212 
quarantine,  214 
route  of  transmission,  212 
source  of  infection,  212 


Rat  as  source  of  infection,  203 
extermination  of,  205 
harbourage,  205-206 
migrations  of,  205 
proofing,  205-295 
Recessive  characters,  261 
Reciprocal  notification,  85 
Registration  area  for  births  and  deaths, 

316 
Regulations,  public  health,  332 
Relapsing  fever,  European,  communi- 
cability, period  of,  200 
disinfection,  201 
exit  of  infective  agent,  199 
immunization,  200 
incubation  period,  199 
infective  agent,  199 
isolation,  200 
methods  of  control,  200 
quarantine,  200 
route  of  transmission,  199 
source  of  infection,  199 
Relaxation,  hygiene  of,  292 
Reportable  diseases,  selection  of,  323 

list  of,  84 
Resistance  of  animal  infective  agents, 

3i 
of  bacteria  to  desiccation,  31 
to  sunlight,  30 
Rest,  hygiene  of,  292 
Restaurants,  226 
Reversionary  inheritance,  264 
Rockefeller  foundation,  335 
Rodents,  203-210 

destruction  by  fumigation,  187 
Round  back,  275 

Routes  of    infection,  classification  of, 
32 
of    transference,     classification    of, 

32 
Rural  population,  308 

Sanitation,  definition  of,  17 

Scarlet  fever,  communicability,  period 

of,  55 
disinfection,  55 
entrance  of,  55 


INDEX 


349 


Scarlet  fever,  exit  of,  55 
general  measures,  55 
incubation  period,  55 
infective  agent,  54 
isolation,  55 
method  of  control,  55 
quarantine,  55 
route  of  transmission,  55 
source  of  infection,  55 
Schick  reaction,  60 
School  children,  medical  inspection  of, 

281 
Schools,    heating   and    ventilation   of, 
279 
lighting  of,  278 
sanitation  of,  278 
Scoliosis,  276 
Screening  of  dwellings,  299 

sewage,  109 
Scurvy,  definition  of,  230 
distribution,  230 
etiology,  past  ideas,  231 

present  ideas,  231 
incidence,  231 
prevention,  233 
public  protection,  234 
Seating  at  school,  280 
Secondary  case,  definition  of,  25 
Sedimentation  of  sewage,  109 

of  water,  133 
Segregation  of  feeble  minded,  266 
Semmelweis,  256 

Septic  sore  throat,  communicability, 
period  of,  56 
disinfection,  56 
entrance,  of,  56 
exit  of,  55 

general  measures,  56 
incubation  period,  56 
infective  agent,  55 
isolation,  56 
methods  of  control,  56 
route  of  transmission,  56 
source  of  infection,  56 
tanks,  109 
Settling  tanks,  109 
Sewage,  composition  of,  105 


Sewage,  conditions  making  treatment 
necessary,  107 
definition  of,  105 
disposal  by  dilution,  106 
limiting  factors,  107 
results  when  satisfactory,  107 

when  unsatisfactory,  107 
effluents  and  relation  to  anthrax, 
216 
finishing  processes,  116 
operation  of  plants,  109 
preparatory  processes,  109 
purification  processes,  114 
results  sought  in  treatment,  107 
selection     of     treatment     methods, 

108 
treatment,  107 
Sewerage,  definition  of,  105 

system,  parts  of,  105 
Sewers,  combined,  105 
sanitary,  105 
storm,  105 
Sexes,  ratio  of,  308 
Sheep  grazing,  210 
Shell  fish,  176 
Siderosis,  253 
Silicosis,  253 
Simplex  combinations  of  determiners, 

263 
Slaughtering  methods,  effect  on  meat, 

i75 
Sleeping  quarters,  297 
Sludge  disposal,  112 
Small-pox,  communicability,  period  of, 
48 

disinfection,  49 

entrance  of  infective  agent,  48 

exit  of  infective  agent,  48 

general  measures,  49 

immunization,  49 

incubation  period,  48 

infective  agent,  48 

methods  of  control,  48 

quarantine,  49 

route  of  transmission,  48 

source  of  infection,  48 
Smith  and  Kilbourne,  22 


35° 


INDEX 


Sources  of  infection,  classification,  26 
definition  of,  25 
influence    of    different    types    of 

sources,  36 
lower  animals  as,  27 
of  anthrax,  215 
of  chicken  pox,  50 
of  cholera,  69 
of  dengue,  196 
of  diphtheria,  59 
of  dysentery,  amoebic,  70 

bacillary,  71 
of  german  measles,  54 
of  gonorrhea,  42 
of  influenza,  57 
of  leprosy,  65 
of  malaria,  188 
of  measles,  51 
of  meningitis,  61 
of  mumps,  52 
of  plague,  203 
of  pneumonia,  63 
of  poliomyelitis,  63 
of  rabies,  212 
of  relapsing  fever,  199 
of  scarlet  fever,  55 
of  small  pox,  48 
of  spotted  fever,  Rocky  Mountain, 

210 
of  septic  sore  throat,  55 
of  syphilis,  41 
of  tetanus,  217 
of  tuberculosis,  64 
of  typhoid,  67 
of  typhus,  197 
of  uncinariasis,  72 
of  whooping  cough,  56 
of  yellow  fever,  195 
Spotted  fever,  Rocky  Mountain,  com- 
municability,  period  of,  210 

disinfection,  210 

entrance  of,  210 

exit  of  infective  agent,  210 

general  measures,  210 

immunization,  210 

incubation  period,  210 

infective  agent,  210 


Spotted      fever,     Rocky     Mountain, 
isolation,  210 
methods  of  control,  210 
quarantine,  210 
route  of  transmission,  210 
source  of  infection,  210 
Springs,  protection  of,  145-146 
Stage,  non-infective,  29 

of  invasion,  29 
State  public  health  administration,  330 
Statistics,  definition  of,  301 

vital,  value  of,  301-310 
Stegomyia  mosquito,  196 
Sequelae  of  infectious  diseases,  220 
Sterilization,  99 

of  feeble  minded,  265 
Still  births,  312 
Storage  of  water,  132 
Sulphur  dioxid  as  insecticide,  101-186 

as  fumigant,  100 
Susceptibles,  81 
Syphilis,  communicability,  period  of,  41 

disinfection,  42 

entrance  of  infective  agent,  41 

exit  of  infective  agent,  41 

general  measures,  42 

incubation  period,  41 

infective  agent,  42 

isolation,  42 

methods  of  control,  41 

route  of  transmission,  41 

source  of  infection,  41 

Temperature,    effect    of,  on    bodily 
comfort,  283 
on  insect  vectors,  180-182 

in  relation  to  milk,  153 
Tetanus,  antitoxin,  employment  of,  21S 

communicability,  period  of,  217 

disinfection,  218 

entrance  of,  217 

exit  of  infective  agent,  217 

general  measures,  218 

immunization,  217 

incubation  period,  217 

infective  agent,  217 

isolation,  217 


INDEX 


351 


Tetanus,  method  of  control,  217 
quarantine,  218 
route  of  transmission,  217 
source  of  infection,  217 
Throat,  hygiene  of,  277 
Ticks,  210-211 
Tieche  test,  48 
Tobaccosis,  253 
Toilet  facilities  at  schools,  280 
Trachoma,  276 

Training  of  water  courses,  191 
Transmission,  routes  of,  classification 

of,  32 
Transportation  hazards,  241 

of  infective  agents  by  insects,  180 
factors  influencing,  182 
Trichiniasis,  176-203 
Tuberculosis,   as    a    cause    of    infant 
mortality,  270 
bovine,  203 

in  milk,  169 
communicability,  period  of,  64 
disinfection,  65 
entrance  of,  64 
exit  of  infective  agent,  64 
general  measures,  65 
incubation  period,  64 
infective  agent,  64 
incidence    among    those    in    dusty 

trades,  252 
isolation,  65 
methods  of  control,  65 
route  of  transmission,  64 
source  of  infection,  64 
Typhoid  fever,  milk  borne,  170 

paratyphoid    (enteric)   group,  com- 
municability, period  of,  67 
disinfection,  68 
entrance  of,  67 
exit  of,  67 

general  measures,  68-69 
immunization,  68 
incubation  period,  67 
infective  agent,  67 
isolation,  68 
methods  of  control,  67 
quarantine,  68 


Typhoid  fever,  paratyphoid   (enteric) 
group,  route   of   transmis- 
sion, 67 
source  of  infection,  67 
Typhus  fever,  communicability,  period 
of,  197 
disinfection,  197 
entrance  of,  197 
exii  of  infective  agent,  197 
general  measures,  198 
immunization,  197 
incubation  period,  197 
infective  agent,  197 
isolation,  197 
methods  of  control,  197 
quarantine,  197 
route  of  transmission,  197 
source  of  infection,  197 

Uncinariasis,    communicability, 
period  of,  72 

disinfection,  73 

entrance  of,  72 

exit  of  infective  agent,  72 

general  measures,  73 

immunization,  73 

incubation  period,  72 

infective  agent,  72 

isolation,  73 

methods  of  control,  73 

quarantine,  73 

route  of  transmission,  72 

source  of  infection,  72 
Urban  population,  308 
Utensils,    eating,    sterilization   of,  227 

milking,  sterilization  of,  152 

Vaccination,    gonorrhea,    43 

influenza,  57 

meningitis,  62 

pneumonia,  64 

small  pox,  49 

accelerated  reaction,  50 
course  of  eruption,  49 
immediate  reaction,  50 
in  infancy,  274 
of  exposed  persons,  50 
primary  take,  49 


352 


INDEX 


Vaccination,  small-pox,  re-vaccination, 
course  of,  50 
technique  of,  49 
vaccine  virus,  49 
typhoid,  68 
whooping  cough,  57 
Varioloid,  50 
Vector,  definition  of,  25 
Vegetables,  fresh,  as  route  of  infection, 

178 
Venereal    diseases    (see    syphilis    and 
gonorrhea), 
medical  prophylaxis  of,  45 
prevalence  of,  43 

standards   for   discharge   of   car- 
riers, 45 
Ventilation,  artificial,  286 
domestic,  297 
natural,  286 
of  schools,  279 

poor,   as   occupational  hazard,    237 
Vision,  defective,  276 
Vital  statistics,  301-310 
Vitamines,  233 

Water,  conditions  favoring   contam- 
ination, 124 
consumption  of,  129 
domestic  supplies,  145 
hygienic  examination  of,  126 
importance  of,  124 
impurities,  permissible  limits  for,  129 
inorganic  poisoning  from,  125 
relationship  to  health  and  disease, 

124 
source  of  supplies,  126 
standards  for,  121 

transfer  of  infective  agents  by,  125 
treatment  of,  coagulation,  133 
disinfection  of,  138 
filtration  of,  135 
results  of,  143 
sedimentation,  133 


Water,  treatment  of,  storage  of,  132 
undesirable  qualities,  131 
water  borne  epidemics,  125 
Welfare,  child,  centers,  273 
Wells,  pollution  of,  145 

protection  of,  146 
Whooping   cough   as   cause   of  infant 
mortality,  269 

communicability,  period  of,  56 

disinfection,  57 

entrance  of,  56 

exit  of,  56 

general  measures,  57 

immunization,  57 

incubation  period,  56 

infective  agent,  56 

isolation,  57 

methods  of  control,  57 

quarantine,  57 

route  of  transmission,  56 

source  of  infection,  56 
Wool,    value   as    fabric   for    clothing, 

294 

Yellow  fever,  communicability,  period 
of,  196 

disinfection,  196 

entrance  of,  195 

epidemic  measures,  196 

exit  of  infective  agent,  195 

general  measures,  196 

immunization,  196 

incubation  period,  195 

infective  agent,  195 

isolation,  196 

methods  of  control,  196 

mosquito,  196 

quarantine,  196 

route  of  transmission,  195 

source  of  infection,  195 
Yersin's  serum,  205 

Zinc  poisoning,  252 


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